diff --git a/Gems/Blast/Code/Tests/Mocks/BlastMocks.h b/Gems/Blast/Code/Tests/Mocks/BlastMocks.h
index 6975573a73..0733862e25 100644
--- a/Gems/Blast/Code/Tests/Mocks/BlastMocks.h
+++ b/Gems/Blast/Code/Tests/Mocks/BlastMocks.h
@@ -68,7 +68,7 @@ namespace Blast
 
         uint32_t getChunkCount() const override
         {
-            return m_chunks.size();
+            return static_cast<uint32_t>(m_chunks.size());
         }
 
         const Nv::Blast::ExtPxChunk* getChunks() const override
@@ -78,7 +78,7 @@ namespace Blast
 
         uint32_t getSubchunkCount() const override
         {
-            return m_subchunks.size();
+            return static_cast<uint32_t>(m_subchunks.size());
         }
 
         const Nv::Blast::ExtPxSubchunk* getSubchunks() const override