diff --git a/CHANGELOG.md b/CHANGELOG.md
index c34b38a77..e455a6d4f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -152,6 +152,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Changed `cluster.reroute`'s `metric` path param to use an enum of metrics ([#586](https://github.com/opensearch-project/opensearch-api-specification/pull/586))
 - Changed `indices.stats`'s `metric` path param to use an enum of metrics ([#586](https://github.com/opensearch-project/opensearch-api-specification/pull/586))
 - Changed `CleanupRepositoryResults`' properties to be `int64`s ([#587](https://github.com/opensearch-project/opensearch-api-specification/pull/587))
+- Added `/_list/indices` & `/_list/shards` api specs ([#613](https://github.com/opensearch-project/opensearch-api-specification/pull/613))
 
 ### Deprecated
 
diff --git a/spec/namespaces/list.yaml b/spec/namespaces/list.yaml
new file mode 100644
index 000000000..b0dddcd86
--- /dev/null
+++ b/spec/namespaces/list.yaml
@@ -0,0 +1,487 @@
+openapi: 3.1.0
+info:
+  title: OpenSearch List API
+  description: OpenSearch List API.
+  version: 1.0.0
+paths:
+  /_list:
+    get:
+      operationId: list.help.0
+      x-operation-group: list.help
+      x-version-added: '2.18'
+      description: Returns help for the List APIs.
+      externalDocs:
+        url: https://opensearch.org/docs/latest/api-reference/list/index/
+      responses:
+        '200':
+          $ref: '#/components/responses/list.help@200'
+  /_list/indices:
+    get:
+      operationId: list.indices.0
+      x-operation-group: list.indices
+      x-version-added: '2.18'
+      description: Returns paginated information about indexes including number of primaries and replicas, document counts, disk size.
+      externalDocs:
+        url: https://opensearch.org/docs/latest/api-reference/list/list-indices/
+      parameters:
+        - $ref: '#/components/parameters/list.indices::query.bytes'
+        - $ref: '#/components/parameters/list.indices::query.cluster_manager_timeout'
+        - $ref: '#/components/parameters/list.indices::query.expand_wildcards'
+        - $ref: '#/components/parameters/list.indices::query.format'
+        - $ref: '#/components/parameters/list.indices::query.h'
+        - $ref: '#/components/parameters/list.indices::query.health'
+        - $ref: '#/components/parameters/list.indices::query.help'
+        - $ref: '#/components/parameters/list.indices::query.include_unloaded_segments'
+        - $ref: '#/components/parameters/list.indices::query.local'
+        - $ref: '#/components/parameters/list.indices::query.master_timeout'
+        - $ref: '#/components/parameters/list.indices::query.next_token'
+        - $ref: '#/components/parameters/list.indices::query.pri'
+        - $ref: '#/components/parameters/list.indices::query.s'
+        - $ref: '#/components/parameters/list.indices::query.size'
+        - $ref: '#/components/parameters/list.indices::query.sort'
+        - $ref: '#/components/parameters/list.indices::query.time'
+        - $ref: '#/components/parameters/list.indices::query.v'
+      responses:
+        '200':
+          $ref: '#/components/responses/list.indices@200'
+  /_list/indices/{index}:
+    get:
+      operationId: list.indices.1
+      x-operation-group: list.indices
+      x-version-added: '2.18'
+      description: Returns paginated information about indexes including number of primaries and replicas, document counts, disk size.
+      externalDocs:
+        url: https://opensearch.org/docs/latest/api-reference/list/list-indices/
+      parameters:
+        - $ref: '#/components/parameters/list.indices::path.index'
+        - $ref: '#/components/parameters/list.indices::query.bytes'
+        - $ref: '#/components/parameters/list.indices::query.cluster_manager_timeout'
+        - $ref: '#/components/parameters/list.indices::query.expand_wildcards'
+        - $ref: '#/components/parameters/list.indices::query.format'
+        - $ref: '#/components/parameters/list.indices::query.h'
+        - $ref: '#/components/parameters/list.indices::query.health'
+        - $ref: '#/components/parameters/list.indices::query.help'
+        - $ref: '#/components/parameters/list.indices::query.include_unloaded_segments'
+        - $ref: '#/components/parameters/list.indices::query.local'
+        - $ref: '#/components/parameters/list.indices::query.master_timeout'
+        - $ref: '#/components/parameters/list.indices::query.next_token'
+        - $ref: '#/components/parameters/list.indices::query.pri'
+        - $ref: '#/components/parameters/list.indices::query.s'
+        - $ref: '#/components/parameters/list.indices::query.size'
+        - $ref: '#/components/parameters/list.indices::query.sort'
+        - $ref: '#/components/parameters/list.indices::query.time'
+        - $ref: '#/components/parameters/list.indices::query.v'
+      responses:
+        '200':
+          $ref: '#/components/responses/list.indices@200'
+  /_list/shards:
+    get:
+      operationId: list.shards.0
+      x-operation-group: list.shards
+      x-version-added: '2.18'
+      description: Returns paginated details of shard allocation on nodes.
+      externalDocs:
+        url: https://opensearch.org/docs/latest/api-reference/list/list-shards/
+      parameters:
+        - $ref: '#/components/parameters/list.shards::query.bytes'
+        - $ref: '#/components/parameters/list.shards::query.cluster_manager_timeout'
+        - $ref: '#/components/parameters/list.shards::query.format'
+        - $ref: '#/components/parameters/list.shards::query.h'
+        - $ref: '#/components/parameters/list.shards::query.help'
+        - $ref: '#/components/parameters/list.shards::query.local'
+        - $ref: '#/components/parameters/list.shards::query.master_timeout'
+        - $ref: '#/components/parameters/list.shards::query.next_token'
+        - $ref: '#/components/parameters/list.shards::query.s'
+        - $ref: '#/components/parameters/list.shards::query.size'
+        - $ref: '#/components/parameters/list.shards::query.sort'
+        - $ref: '#/components/parameters/list.shards::query.time'
+        - $ref: '#/components/parameters/list.shards::query.v'
+      responses:
+        '200':
+          $ref: '#/components/responses/list.shards@200'
+  /_list/shards/{index}:
+    get:
+      operationId: list.shards.1
+      x-operation-group: list.shards
+      x-version-added: '2.18'
+      description: Returns paginated details of shard allocation on nodes.
+      externalDocs:
+        url: https://opensearch.org/docs/latest/api-reference/list/list-shards/
+      parameters:
+        - $ref: '#/components/parameters/list.shards::path.index'
+        - $ref: '#/components/parameters/list.shards::query.bytes'
+        - $ref: '#/components/parameters/list.shards::query.cluster_manager_timeout'
+        - $ref: '#/components/parameters/list.shards::query.format'
+        - $ref: '#/components/parameters/list.shards::query.h'
+        - $ref: '#/components/parameters/list.shards::query.help'
+        - $ref: '#/components/parameters/list.shards::query.local'
+        - $ref: '#/components/parameters/list.shards::query.master_timeout'
+        - $ref: '#/components/parameters/list.shards::query.next_token'
+        - $ref: '#/components/parameters/list.shards::query.s'
+        - $ref: '#/components/parameters/list.shards::query.size'
+        - $ref: '#/components/parameters/list.shards::query.sort'
+        - $ref: '#/components/parameters/list.shards::query.time'
+        - $ref: '#/components/parameters/list.shards::query.v'
+      responses:
+        '200':
+          $ref: '#/components/responses/list.shards@200'
+components:
+  responses:
+    list.help@200:
+      content:
+        text/plain:
+          schema:
+            type: string
+    list.indices@200:
+      content:
+        text/plain:
+          schema:
+            type: string
+        application/json:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              indices:
+                type: array
+                items:
+                  $ref: '../schemas/cat.indices.yaml#/components/schemas/IndicesRecord'
+        application/yaml:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              indices:
+                type: array
+                items:
+                  $ref: '../schemas/cat.indices.yaml#/components/schemas/IndicesRecord'
+        application/cbor:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              indices:
+                type: array
+                items:
+                  $ref: '../schemas/cat.indices.yaml#/components/schemas/IndicesRecord'
+        application/smile:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              indices:
+                type: array
+                items:
+                  $ref: '../schemas/cat.indices.yaml#/components/schemas/IndicesRecord'
+    list.shards@200:
+      content:
+        text/plain:
+          schema:
+            type: string
+        application/json:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              shards:
+                type: array
+                items:
+                  $ref: '../schemas/cat.shards.yaml#/components/schemas/ShardsRecord'
+        application/yaml:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              shards:
+                type: array
+                items:
+                  $ref: '../schemas/cat.shards.yaml#/components/schemas/ShardsRecord'
+        application/cbor:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              shards:
+                type: array
+                items:
+                  $ref: '../schemas/cat.shards.yaml#/components/schemas/ShardsRecord'
+        application/smile:
+          schema:
+            type: object
+            properties:
+              next_token:
+                type: ['null', string]
+              shards:
+                type: array
+                items:
+                  $ref: '../schemas/cat.shards.yaml#/components/schemas/ShardsRecord'
+  parameters:
+    list.indices::path.index:
+      in: path
+      name: index
+      description: |-
+        Comma-separated list of data streams, indexes, and aliases used to limit the request.
+        Supports wildcards (`*`). To target all data streams and indexes, omit this parameter or use `*` or `_all`.
+      required: true
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/Indices'
+      style: simple
+    list.indices::query.bytes:
+      in: query
+      name: bytes
+      description: The unit used to display byte values.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/ByteUnit'
+      style: form
+    list.indices::query.cluster_manager_timeout:
+      name: cluster_manager_timeout
+      in: query
+      description: Operation timeout for connection to cluster-manager node.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/Duration'
+      x-version-added: '2.0'
+    list.indices::query.expand_wildcards:
+      in: query
+      name: expand_wildcards
+      description: The type of index that wildcard patterns can match.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/ExpandWildcards'
+      style: form
+    list.indices::query.format:
+      name: format
+      in: query
+      description: A short version of the Accept header, such as `JSON`, `YAML`.
+      schema:
+        type: string
+        description: A short version of the Accept header, such as `JSON`, `YAML`.
+    list.indices::query.h:
+      name: h
+      in: query
+      description: Comma-separated list of column names to display.
+      style: form
+      schema:
+        type: array
+        items:
+          type: string
+        description: Comma-separated list of column names to display.
+      explode: true
+    list.indices::query.health:
+      in: query
+      name: health
+      description: The health status used to limit returned indexes. By default, the response includes indexes of any health status.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/HealthStatus'
+      style: form
+    list.indices::query.help:
+      name: help
+      in: query
+      description: Return help information.
+      schema:
+        type: boolean
+        default: false
+        description: Return help information.
+    list.indices::query.include_unloaded_segments:
+      in: query
+      name: include_unloaded_segments
+      description: If true, the response includes information from segments that are not loaded into memory.
+      schema:
+        type: boolean
+        default: false
+      style: form
+    list.indices::query.local:
+      name: local
+      in: query
+      description: Return local information, do not retrieve the state from cluster-manager node.
+      schema:
+        type: boolean
+        default: false
+        description: Return local information, do not retrieve the state from cluster-manager node.
+    list.indices::query.master_timeout:
+      name: master_timeout
+      in: query
+      description: Operation timeout for connection to cluster manager node.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/Duration'
+      x-version-deprecated: '2.0'
+      x-deprecation-message: To promote inclusive language, use `cluster_manager_timeout` instead.
+      deprecated: true
+    list.indices::query.pri:
+      in: query
+      name: pri
+      description: If true, the response only includes information from primary shards.
+      schema:
+        type: boolean
+        default: false
+      style: form
+    list.indices::query.s:
+      name: s
+      in: query
+      description: Comma-separated list of column names or column aliases to sort by.
+      style: form
+      schema:
+        type: array
+        items:
+          type: string
+        description: Comma-separated list of column names or column aliases to sort by.
+      explode: true
+    list.indices::query.time:
+      in: query
+      name: time
+      description: The unit used to display time values.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/TimeUnit'
+      style: form
+    list.indices::query.v:
+      name: v
+      in: query
+      description: Verbose mode. Display column headers.
+      schema:
+        type: boolean
+        default: false
+        description: Verbose mode. Display column headers.
+    list.indices::query.next_token:
+      name: next_token
+      in: query
+      description: Token to retrieve next page of indexes.
+      schema:
+        type: ['null', string]
+        description: Token to retrieve next page of indexes.
+    list.indices::query.size:
+      name: size
+      in: query
+      description: Maximum number of indexes to be displayed in a page.
+      schema:
+        type: integer
+        format: int32 
+    list.indices::query.sort:
+      name: sort
+      in: query
+      description: Defines order in which indexes will be displayed. Accepted values are `asc` and `desc`. If `desc`, most recently created indexes would be displayed first.
+      schema:
+        type: string
+        enum:
+          - asc
+          - desc
+    list.shards::path.index:
+      in: path
+      name: index
+      description: |-
+        A comma-separated list of data streams, indexes, and aliases used to limit the request.
+        Supports wildcards (`*`).
+        To target all data streams and indexes, omit this parameter or use `*` or `_all`.
+      required: true
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/Indices'
+      style: simple
+    list.shards::query.bytes:
+      in: query
+      name: bytes
+      description: The unit used to display byte values.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/ByteUnit'
+      style: form
+    list.shards::query.cluster_manager_timeout:
+      name: cluster_manager_timeout
+      in: query
+      description: Operation timeout for connection to cluster-manager node.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/Duration'
+      x-version-added: '2.0'
+    list.shards::query.format:
+      name: format
+      in: query
+      description: A short version of the Accept header, such as `JSON`, `YAML`.
+      schema:
+        type: string
+        description: A short version of the Accept header, such as `JSON`, `YAML`.
+    list.shards::query.h:
+      name: h
+      in: query
+      description: Comma-separated list of column names to display.
+      style: form
+      schema:
+        type: array
+        items:
+          type: string
+        description: Comma-separated list of column names to display.
+      explode: true
+    list.shards::query.help:
+      name: help
+      in: query
+      description: Return help information.
+      schema:
+        type: boolean
+        default: false
+        description: Return help information.
+    list.shards::query.local:
+      name: local
+      in: query
+      description: Return local information, do not retrieve the state from cluster-manager node.
+      schema:
+        type: boolean
+        default: false
+        description: Return local information, do not retrieve the state from cluster-manager node.
+    list.shards::query.master_timeout:
+      name: master_timeout
+      in: query
+      description: Operation timeout for connection to cluster manager node.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/Duration'
+      x-version-deprecated: '2.0'
+      x-deprecation-message: To promote inclusive language, use 'cluster_manager_timeout' instead.
+      deprecated: true
+    list.shards::query.s:
+      name: s
+      in: query
+      description: Comma-separated list of column names or column aliases to sort by.
+      style: form
+      schema:
+        type: array
+        items:
+          type: string
+        description: Comma-separated list of column names or column aliases to sort by.
+      explode: true
+    list.shards::query.time:
+      name: time
+      in: query
+      description: The unit in which to display time values.
+      schema:
+        $ref: '../schemas/_common.yaml#/components/schemas/TimeUnit'
+    list.shards::query.v:
+      name: v
+      in: query
+      description: Verbose mode. Display column headers.
+      schema:
+        type: boolean
+        default: false
+        description: Verbose mode. Display column headers.
+    list.shards::query.next_token:
+      name: next_token
+      in: query
+      description: Token to retrieve next page of shards.
+      schema:
+        type: ['null', string]
+        description: Token to retrieve next page of shards.
+    list.shards::query.size:
+      name: size
+      in: query
+      description: Maximum number of shards to be displayed in a page.
+      schema:
+        type: integer
+        format: int32 
+    list.shards::query.sort:
+      name: sort
+      in: query
+      description: Defines order in which shards will be displayed. Accepted values are `asc` and `desc`. If `desc`, most recently created shards would be displayed first.
+      schema:
+        type: string
+        enum:
+          - asc
+          - desc
\ No newline at end of file
diff --git a/tests/default/list/indices.yaml b/tests/default/list/indices.yaml
new file mode 100644
index 000000000..a1407f211
--- /dev/null
+++ b/tests/default/list/indices.yaml
@@ -0,0 +1,141 @@
+$schema: ../../../json_schemas/test_story.schema.yaml
+
+description: Test _list/indices endpoints.
+# TODO: Re-enable in 3.0, see https://github.com/opensearch-project/opensearch-api-specification/pull/613
+version: '>= 2.18 < 3'
+prologues:
+  - path: /{index}
+    method: PUT
+    parameters:
+      index: books
+    request:
+      payload: {}
+  - path: /{index}
+    method: PUT
+    parameters:
+      index: unassigned
+      wait_for_active_shards: 0
+    request:
+      payload:
+        settings:
+          routing:
+            allocation:
+              require:
+                test: test
+epilogues:
+  - path: /books
+    method: DELETE
+    status: [200, 404]
+  - path: /unassigned
+    method: DELETE
+    status: [200, 404]
+chapters:
+  - synopsis: List information related to indexes (text/plain).
+    method: GET
+    path: /_list/indices
+    response:
+      status: 200
+      content_type: text/plain
+  - synopsis: List information related to one index (text/plain).
+    method: GET
+    path: /_list/indices/{index}
+    parameters:
+      index: books
+    response:
+      status: 200
+      content_type: text/plain
+  - synopsis: List information related to indexes with verbose output (v=true).
+    method: GET
+    path: /_list/indices
+    parameters:
+      v: true
+    response:
+      status: 200
+      content_type: text/plain
+  - synopsis: List information related to indexes with headers (h=header1,header2).
+    method: GET
+    path: /_list/indices
+    parameters:
+      h:
+        - health
+        - status
+    response:
+      status: 200
+      content_type: text/plain
+  - synopsis: List information related to indexes displaying all available headers (help=true).
+    method: GET
+    path: /_list/indices
+    parameters:
+      help: true
+    response:
+      status: 200
+      content_type: text/plain
+  - synopsis: List information related to indexes with sorted results.
+    method: GET
+    path: /_list/indices
+    parameters:
+      s:
+        - status
+    response:
+      status: 200
+      content_type: text/plain
+  - synopsis: List information related to indexes with bytes, time and all fields.
+    method: GET
+    path: /_list/indices
+    parameters:
+      format: json
+      bytes: b
+      time: s
+      h:
+        - '*'
+    response:
+      status: 200
+      content_type: application/json
+  - synopsis: List information related to indexes with all fields.
+    method: GET
+    path: /_list/indices
+    parameters:
+      format: json
+    response:
+      status: 200
+      content_type: application/json
+  - synopsis: List information related to indexes in different formats (format=json).
+    method: GET
+    path: /_list/indices
+    parameters:
+      format: json
+    response:
+      status: 200
+      content_type: application/json
+  - synopsis: List information related to indexes in different formats (format=yaml).
+    method: GET
+    path: /_list/indices
+    parameters:
+      format: yaml
+    response:
+      status: 200
+      content_type: application/yaml
+  - synopsis: List information related to indexes in different formats (format=cbor).
+    distributions:
+      excluded:
+        - amazon-managed
+        - amazon-serverless
+    method: GET
+    path: /_list/indices
+    parameters:
+      format: cbor
+    response:
+      status: 200
+      content_type: application/cbor
+  - synopsis: List information related to indexes in different formats (format=smile).
+    distributions:
+      excluded:
+        - amazon-managed
+        - amazon-serverless
+    method: GET
+    path: /_list/indices
+    parameters:
+      format: smile
+    response:
+      status: 200
+      content_type: application/smile
diff --git a/tests/default/list/shards.yaml b/tests/default/list/shards.yaml
new file mode 100644
index 000000000..768804c8a
--- /dev/null
+++ b/tests/default/list/shards.yaml
@@ -0,0 +1,51 @@
+$schema: ../../../json_schemas/test_story.schema.yaml
+
+description: Test list/shards endpoints.
+# TODO: Re-enable in 3.0, see https://github.com/opensearch-project/opensearch-api-specification/pull/613
+version: '>= 2.18 < 3'
+prologues:
+  - path: /{index}
+    method: PUT
+    parameters:
+      index: games
+  - path: /{index}
+    method: PUT
+    parameters:
+      index: unassigned
+      wait_for_active_shards: 0
+    request:
+      payload:
+        settings:
+          routing:
+            allocation:
+              require:
+                test: test
+epilogues:
+  - path: /games
+    method: DELETE
+    status: [200, 404]
+  - path: /unassigned
+    method: DELETE
+    status: [200, 404]
+chapters:
+  - synopsis: List the state of all primary and replica shards and how they are distributed.
+    path: /_list/shards
+    method: GET
+    parameters:
+      format: json
+      h:
+        - '*'
+  - synopsis: List the state of all primary and replica shards and how they are distributed for an index.
+    path: /_list/shards/{index}
+    method: GET
+    parameters:
+      format: json
+      index:
+        - games
+      bytes: kb
+      local: true
+      time: s
+      h:
+        - '*'
+    response:
+      status: 200