diff --git a/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/AbstractRestClientConfigBuilder.java b/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/AbstractRestClientConfigBuilder.java
index 1f0d37b0ca1551..26faff8777282a 100644
--- a/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/AbstractRestClientConfigBuilder.java
+++ b/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/AbstractRestClientConfigBuilder.java
@@ -53,9 +53,19 @@
 public abstract class AbstractRestClientConfigBuilder implements ConfigBuilder {
     private static final String REST_CLIENT_PREFIX = "quarkus.rest-client.";
 
+    private final boolean runtime;
+
+    public AbstractRestClientConfigBuilder() {
+        this.runtime = true;
+        RestClientsConfig.RestClientKeysProvider.KEYS.clear();
+    }
+
+    public AbstractRestClientConfigBuilder(boolean runtime) {
+        this.runtime = runtime;
+    }
+
     @Override
     public SmallRyeConfigBuilder configBuilder(final SmallRyeConfigBuilder builder) {
-        RestClientsConfig.RestClientKeysProvider.KEYS.clear();
         List<RegisteredRestClient> restClients = getRestClients();
 
         Map<String, String> quarkusFallbacks = new HashMap<>();
@@ -63,7 +73,9 @@ public SmallRyeConfigBuilder configBuilder(final SmallRyeConfigBuilder builder)
         // relocates [All Combinations] -> quarkus.rest-client."FQN".*
         Map<String, String> relocates = new HashMap<>();
         for (RegisteredRestClient restClient : restClients) {
-            RestClientsConfig.RestClientKeysProvider.KEYS.add(restClient.getFullName());
+            if (runtime) {
+                RestClientsConfig.RestClientKeysProvider.KEYS.add(restClient.getFullName());
+            }
 
             // FQN -> Simple Name
             String quotedFullName = "\"" + restClient.getFullName() + "\"";
diff --git a/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/RestClientsBuildTimeConfig.java b/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/RestClientsBuildTimeConfig.java
index 192c41fd1c72dc..47df726193404d 100644
--- a/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/RestClientsBuildTimeConfig.java
+++ b/extensions/resteasy-classic/rest-client-config/runtime/src/main/java/io/quarkus/restclient/config/RestClientsBuildTimeConfig.java
@@ -143,7 +143,7 @@ private ConfigSource getDefaultsSource() {
                 .withCustomizers(new SmallRyeConfigBuilderCustomizer() {
                     @Override
                     public void configBuilder(final SmallRyeConfigBuilder builder) {
-                        new AbstractRestClientConfigBuilder() {
+                        new AbstractRestClientConfigBuilder(false) {
                             @Override
                             public List<RegisteredRestClient> getRestClients() {
                                 return restClients;