diff --git a/sdk/storage/azure-storage-files-shares/CHANGELOG.md b/sdk/storage/azure-storage-files-shares/CHANGELOG.md
index 1942e1f71..32d7fe44e 100644
--- a/sdk/storage/azure-storage-files-shares/CHANGELOG.md
+++ b/sdk/storage/azure-storage-files-shares/CHANGELOG.md
@@ -6,6 +6,8 @@
 
 ### Breaking Changes
 
+- `AccessPolicy::StartsOn` and `AccessPolicy::ExpiresOn` are now nullable values.
+
 ### Bugs Fixed
 
 ### Other Changes
diff --git a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/protocol/share_rest_client.hpp b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/protocol/share_rest_client.hpp
index 0faad0334..177c7a9fc 100644
--- a/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/protocol/share_rest_client.hpp
+++ b/sdk/storage/azure-storage-files-shares/inc/azure/storage/files/shares/protocol/share_rest_client.hpp
@@ -178,12 +178,12 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
       /**
        * The date-time the policy is active.
        */
-      DateTime StartsOn;
+      Azure::Nullable<DateTime> StartsOn;
 
       /**
        * The date-time the policy expires.
        */
-      DateTime ExpiresOn;
+      Azure::Nullable<DateTime> ExpiresOn;
 
       /**
        * The permissions for the ACL policy.
@@ -5007,20 +5007,28 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares {
         static void AccessPolicyToXml(_internal::XmlWriter& writer, const AccessPolicy& object)
         {
           writer.Write(_internal::XmlNode{_internal::XmlNodeType::StartTag, "AccessPolicy"});
-          writer.Write(_internal::XmlNode{_internal::XmlNodeType::StartTag, "Start"});
-          writer.Write(_internal::XmlNode{
-              _internal::XmlNodeType::Text,
-              std::string(),
-              object.StartsOn.ToString(
-                  Azure::DateTime::DateFormat::Rfc3339, DateTime::TimeFractionFormat::AllDigits)});
-          writer.Write(_internal::XmlNode{_internal::XmlNodeType::EndTag});
-          writer.Write(_internal::XmlNode{_internal::XmlNodeType::StartTag, "Expiry"});
-          writer.Write(_internal::XmlNode{
-              _internal::XmlNodeType::Text,
-              std::string(),
-              object.ExpiresOn.ToString(
-                  Azure::DateTime::DateFormat::Rfc3339, DateTime::TimeFractionFormat::AllDigits)});
-          writer.Write(_internal::XmlNode{_internal::XmlNodeType::EndTag});
+          if (object.StartsOn.HasValue())
+          {
+            writer.Write(_internal::XmlNode{_internal::XmlNodeType::StartTag, "Start"});
+            writer.Write(_internal::XmlNode{
+                _internal::XmlNodeType::Text,
+                std::string(),
+                object.StartsOn.Value().ToString(
+                    Azure::DateTime::DateFormat::Rfc3339,
+                    DateTime::TimeFractionFormat::AllDigits)});
+            writer.Write(_internal::XmlNode{_internal::XmlNodeType::EndTag});
+          }
+          if (object.ExpiresOn.HasValue())
+          {
+            writer.Write(_internal::XmlNode{_internal::XmlNodeType::StartTag, "Expiry"});
+            writer.Write(_internal::XmlNode{
+                _internal::XmlNodeType::Text,
+                std::string(),
+                object.ExpiresOn.Value().ToString(
+                    Azure::DateTime::DateFormat::Rfc3339,
+                    DateTime::TimeFractionFormat::AllDigits)});
+            writer.Write(_internal::XmlNode{_internal::XmlNodeType::EndTag});
+          }
           writer.Write(_internal::XmlNode{_internal::XmlNodeType::StartTag, "Permission"});
           writer.Write(
               _internal::XmlNode{_internal::XmlNodeType::Text, std::string(), object.Permission});
diff --git a/sdk/storage/azure-storage-files-shares/test/share_client_test.cpp b/sdk/storage/azure-storage-files-shares/test/share_client_test.cpp
index a350321a0..f72dab390 100644
--- a/sdk/storage/azure-storage-files-shares/test/share_client_test.cpp
+++ b/sdk/storage/azure-storage-files-shares/test/share_client_test.cpp
@@ -14,8 +14,12 @@ namespace Azure { namespace Storage { namespace Files { namespace Shares { names
       const Azure::Storage::Files::Shares::Models::SignedIdentifier& lhs,
       const Azure::Storage::Files::Shares::Models::SignedIdentifier& rhs)
   {
-    return lhs.Id == rhs.Id && lhs.Policy.StartsOn == rhs.Policy.StartsOn
-        && lhs.Policy.ExpiresOn == rhs.Policy.ExpiresOn
+    return lhs.Id == rhs.Id && lhs.Policy.StartsOn.HasValue() == rhs.Policy.StartsOn.HasValue()
+        && (!lhs.Policy.StartsOn.HasValue()
+            || lhs.Policy.StartsOn.Value() == rhs.Policy.StartsOn.Value())
+        && lhs.Policy.ExpiresOn.HasValue() == rhs.Policy.ExpiresOn.HasValue()
+        && (!lhs.Policy.ExpiresOn.HasValue()
+            || lhs.Policy.ExpiresOn.Value() == rhs.Policy.ExpiresOn.Value())
         && lhs.Policy.Permission == rhs.Policy.Permission;
   }
 
@@ -213,6 +217,37 @@ namespace Azure { namespace Storage { namespace Test {
     EXPECT_EQ(ret2.Value.SignedIdentifiers, identifiers);
   }
 
+  TEST_F(FileShareClientTest, ShareAccessPolicyNullable)
+  {
+    std::vector<Files::Shares::Models::SignedIdentifier> identifiers;
+    {
+      Files::Shares::Models::SignedIdentifier identifier;
+      identifier.Id = RandomString(64);
+      identifier.Policy.Permission = "r";
+      identifiers.emplace_back(identifier);
+    }
+    {
+      Files::Shares::Models::SignedIdentifier identifier;
+      identifier.Id = RandomString(64);
+      identifier.Policy.StartsOn = std::chrono::system_clock::now() - std::chrono::minutes(10);
+      identifier.Policy.Permission = "r";
+      identifiers.emplace_back(identifier);
+    }
+    {
+      Files::Shares::Models::SignedIdentifier identifier;
+      identifier.Id = RandomString(64);
+      identifier.Policy.ExpiresOn = std::chrono::system_clock::now() + std::chrono::minutes(100);
+      identifier.Policy.Permission = "r";
+      identifiers.emplace_back(identifier);
+    }
+
+    auto ret = m_shareClient->SetAccessPolicy(identifiers);
+    EXPECT_TRUE(IsValidTime(ret.Value.LastModified));
+
+    auto ret2 = m_shareClient->GetAccessPolicy();
+    EXPECT_EQ(ret2.Value.SignedIdentifiers, identifiers);
+  }
+
   TEST_F(FileShareClientTest, SharePermissions)
   {
     std::string permission = "O:S-1-5-21-2127521184-1604012920-1887927527-21560751G:S-1-5-21-"