diff --git a/source/adios2/CMakeLists.txt b/source/adios2/CMakeLists.txt
index b9c7b7a4ab..3bf8fe2e4d 100644
--- a/source/adios2/CMakeLists.txt
+++ b/source/adios2/CMakeLists.txt
@@ -15,6 +15,7 @@ add_library(adios2_core
   core/Stream.cpp core/Stream.tcc
   core/Variable.cpp core/Variable.tcc
   core/VariableBase.cpp
+  core/Span.cpp core/Span.tcc
   core/Group.cpp core/Group.tcc
 
 #operator
diff --git a/source/adios2/core/Span.cpp b/source/adios2/core/Span.cpp
new file mode 100644
index 0000000000..6fc7019835
--- /dev/null
+++ b/source/adios2/core/Span.cpp
@@ -0,0 +1,23 @@
+/*
+ * Distributed under the OSI-approved Apache License, Version 2.0.  See
+ * accompanying file Copyright.txt for details.
+ *
+ * Span.cpp
+ *
+ *  Created on: Apr 17, 2022
+ *      Author: Jason Wang jason.ruonan.wang@gmail.com
+ */
+
+#include "Span.tcc"
+
+namespace adios2
+{
+namespace core
+{
+
+#define declare_template_instantiation(T) template class Span<T>;
+ADIOS2_FOREACH_PRIMITIVE_STDTYPE_1ARG(declare_template_instantiation)
+#undef declare_type
+
+} // end namespace core
+} // end namespace adios2
diff --git a/source/adios2/core/Span.h b/source/adios2/core/Span.h
new file mode 100644
index 0000000000..d2e97e343f
--- /dev/null
+++ b/source/adios2/core/Span.h
@@ -0,0 +1,53 @@
+/*
+ * Distributed under the OSI-approved Apache License, Version 2.0.  See
+ * accompanying file Copyright.txt for details.
+ *
+ * Span.h
+ *
+ *  Created on: Apr 17, 2022
+ *      Author: Jason Wang jason.ruonan.wang@gmail.com
+ */
+
+#ifndef ADIOS2_CORE_SPAN_H_
+#define ADIOS2_CORE_SPAN_H_
+
+#include "adios2/core/VariableBase.h"
+
+namespace adios2
+{
+namespace core
+{
+
+template <class T>
+class Span
+{
+public:
+    std::pair<size_t, size_t> m_MinMaxMetadataPositions;
+
+    // internal position variables from which the engine
+    // can return a valid pointer any time
+    // BP5 needs two levels of reference, BP3/4 uses only one
+    size_t m_PayloadPosition = 0;
+    int m_BufferIdx = -1;
+
+    T m_Value = T{};
+
+    Span(Engine &engine, const size_t size);
+    ~Span() = default;
+
+    size_t Size() const noexcept;
+    T *Data() const noexcept;
+
+    T &At(const size_t position);
+
+    T &operator[](const size_t position);
+
+private:
+    Engine &m_Engine;
+    size_t m_Size = 0;
+};
+
+} // end namespace core
+} // end namespace adios2
+
+#endif // ADIOS2_CORE_SPAN_H_
diff --git a/source/adios2/core/Span.tcc b/source/adios2/core/Span.tcc
new file mode 100644
index 0000000000..ab7435cdd3
--- /dev/null
+++ b/source/adios2/core/Span.tcc
@@ -0,0 +1,66 @@
+/*
+ * Distributed under the OSI-approved Apache License, Version 2.0.  See
+ * accompanying file Copyright.txt for details.
+ *
+ * Span.tcc
+ *
+ *  Created on: Apr 17, 2022
+ *      Author: Jason Wang jason.ruonan.wang@gmail.com
+ */
+
+#ifndef ADIOS2_CORE_SPAN_TCC_
+#define ADIOS2_CORE_SPAN_TCC_
+
+#include "Span.h"
+
+#include "adios2/core/Engine.h"
+
+namespace adios2
+{
+namespace core
+{
+
+template <class T>
+Span<T>::Span(Engine &engine, const size_t size)
+: m_Engine(engine), m_Size(size)
+{
+}
+
+template <class T>
+size_t Span<T>::Size() const noexcept
+{
+    return m_Size;
+}
+
+template <class T>
+T *Span<T>::Data() const noexcept
+{
+    return m_Engine.BufferData<T>(m_BufferIdx, m_PayloadPosition);
+}
+
+template <class T>
+T &Span<T>::At(const size_t position)
+{
+    if (position > m_Size)
+    {
+        helper::Throw<std::invalid_argument>(
+            "Core", "Span", "At",
+            "position " + std::to_string(position) +
+                " is out of bounds for span of size " + std::to_string(m_Size));
+    }
+
+    return (*this)[position];
+}
+
+template <class T>
+T &Span<T>::operator[](const size_t position)
+{
+    T &data = *m_Engine.BufferData<T>(m_BufferIdx,
+                                      m_PayloadPosition + position * sizeof(T));
+    return data;
+}
+
+} // end namespace core
+} // end namespace adios2
+
+#endif // ADIOS2_CORE_SPAN_TCC_
diff --git a/source/adios2/core/Variable.cpp b/source/adios2/core/Variable.cpp
index 187311e342..5c26fe56db 100644
--- a/source/adios2/core/Variable.cpp
+++ b/source/adios2/core/Variable.cpp
@@ -112,9 +112,5 @@ namespace core
 ADIOS2_FOREACH_STDTYPE_1ARG(declare_type)
 #undef declare_type
 
-#define declare_template_instantiation(T) template class Span<T>;
-ADIOS2_FOREACH_PRIMITIVE_STDTYPE_1ARG(declare_template_instantiation)
-#undef declare_type
-
 } // end namespace core
 } // end namespace adios2
diff --git a/source/adios2/core/Variable.h b/source/adios2/core/Variable.h
index 4b62a912ce..1f4ea40fbf 100644
--- a/source/adios2/core/Variable.h
+++ b/source/adios2/core/Variable.h
@@ -19,6 +19,7 @@
 #include <vector>
 /// \endcond
 
+#include "Span.h"
 #include "adios2/common/ADIOSTypes.h"
 #include "adios2/core/VariableBase.h"
 #include "adios2/helper/adiosMath.h"
@@ -29,38 +30,6 @@ namespace adios2
 namespace core
 {
 
-template <class T>
-class Span
-{
-public:
-    std::pair<size_t, size_t> m_MinMaxDataPositions;
-    std::pair<size_t, size_t> m_MinMaxMetadataPositions;
-
-    // internal position variables from which the engine
-    // can return a valid pointer any time
-    // BP5 needs two levels of reference, BP3/4 uses only one
-    size_t m_PayloadPosition = 0;
-    int m_BufferIdx = -1;
-
-    T m_Value = T{};
-
-    Span(Engine &engine, const size_t size);
-    ~Span() = default;
-
-    size_t Size() const noexcept;
-    T *Data() const noexcept;
-
-    T &At(const size_t position);
-    const T &At(const size_t position) const;
-
-    T &operator[](const size_t position);
-    const T &operator[](const size_t position) const;
-
-private:
-    Engine &m_Engine;
-    size_t m_Size = 0;
-};
-
 /**
  * @param Base (parent) class for template derived (child) class Variable.
  */
diff --git a/source/adios2/core/Variable.tcc b/source/adios2/core/Variable.tcc
index 9beb0b05d6..4f93c933a0 100644
--- a/source/adios2/core/Variable.tcc
+++ b/source/adios2/core/Variable.tcc
@@ -257,70 +257,6 @@ void Variable<T>::CheckRandomAccess(const size_t step,
     }
 }
 
-// Span functions
-template <class T>
-Span<T>::Span(Engine &engine, const size_t size)
-: m_Engine(engine), m_Size(size)
-{
-}
-
-template <class T>
-size_t Span<T>::Size() const noexcept
-{
-    return m_Size;
-}
-
-template <class T>
-T *Span<T>::Data() const noexcept
-{
-    return m_Engine.BufferData<T>(m_BufferIdx, m_PayloadPosition);
-}
-
-template <class T>
-T &Span<T>::At(const size_t position)
-{
-    if (position > m_Size)
-    {
-        helper::Throw<std::invalid_argument>(
-            "Core", "Variable", "At",
-            "position " + std::to_string(position) +
-                " is out of bounds for span of size " + std::to_string(m_Size));
-    }
-
-    return (*this)[position];
-}
-
-template <class T>
-const T &Span<T>::At(const size_t position) const
-{
-    if (position > m_Size)
-    {
-        helper::Throw<std::invalid_argument>(
-            "Core", "Variable", "At",
-            "position " + std::to_string(position) +
-                " is out of bounds for span of size " + std::to_string(m_Size) +
-                " , in call to const T& Span<T>::At");
-    }
-
-    return (*this)[position];
-}
-
-template <class T>
-T &Span<T>::operator[](const size_t position)
-{
-    T &data = *m_Engine.BufferData<T>(m_BufferIdx,
-                                      m_PayloadPosition + position * sizeof(T));
-    return data;
-}
-
-template <class T>
-const T &Span<T>::operator[](const size_t position) const
-{
-    const T &data = *m_Engine.BufferData<T>(
-        m_BufferIdx, m_PayloadPosition + position * sizeof(T));
-    return data;
-}
-
 } // end namespace core
 } // end namespace adios2