diff --git a/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.test.ts b/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.test.ts
index f9323574f5ea..a4d7b5929c89 100644
--- a/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.test.ts
+++ b/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.test.ts
@@ -1,5 +1,5 @@
 import { SyncSchema, SyncSchemaStream } from "core/domain/catalog";
-import { DestinationSyncMode, SyncMode } from "core/request/AirbyteClient";
+import { DestinationSyncMode, StreamDescriptor, SyncMode } from "core/request/AirbyteClient";
 
 import calculateInitialCatalog from "./calculateInitialCatalog";
 
@@ -11,6 +11,7 @@ const mockSyncSchemaStream: SyncSchemaStream = {
     sourceDefinedPrimaryKey: [["new_primary_key"]],
     jsonSchema: {},
     name: "test",
+    namespace: "namespace-test",
     supportedSyncModes: [],
   },
   config: {
@@ -535,4 +536,60 @@ describe("calculateInitialCatalog", () => {
     // cursor field
     expect(calculatedStreams[0].config?.cursorField).toEqual(config?.cursorField);
   });
+
+  it("should calculate optimal sync mode if stream is new", () => {
+    const { stream: sourceDefinedStream, config } = mockSyncSchemaStream;
+
+    const newStreamDescriptors: StreamDescriptor[] = [{ name: "test", namespace: "namespace-test" }];
+
+    const { streams: calculatedStreams } = calculateInitialCatalog(
+      {
+        streams: [
+          {
+            id: "1",
+            stream: {
+              ...sourceDefinedStream,
+              name: "test",
+              namespace: "namespace-test",
+              sourceDefinedCursor: true,
+              defaultCursorField: ["id"],
+              supportedSyncModes: [SyncMode.incremental],
+            },
+            config: {
+              ...config,
+              destinationSyncMode: DestinationSyncMode.overwrite,
+              syncMode: SyncMode.incremental,
+            },
+          },
+          {
+            id: "1",
+            stream: {
+              ...sourceDefinedStream,
+              name: "test2",
+              namespace: "namespace-test",
+              sourceDefinedCursor: true,
+              defaultCursorField: ["id"],
+              supportedSyncModes: [SyncMode.incremental],
+            },
+            config: {
+              ...config,
+              destinationSyncMode: DestinationSyncMode.overwrite,
+              syncMode: SyncMode.incremental,
+            },
+          },
+        ],
+      },
+      [DestinationSyncMode.append_dedup],
+      true,
+      newStreamDescriptors
+    );
+
+    // new stream has its sync mode calculated
+    expect(calculatedStreams[0].config?.syncMode).toEqual(SyncMode.incremental);
+    expect(calculatedStreams[0].config?.destinationSyncMode).toEqual(DestinationSyncMode.append_dedup);
+
+    // existing stream remains as-is
+    expect(calculatedStreams[1].config?.syncMode).toEqual(SyncMode.incremental);
+    expect(calculatedStreams[1].config?.destinationSyncMode).toEqual(DestinationSyncMode.overwrite);
+  });
 });
diff --git a/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.ts b/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.ts
index dcc2876025d9..983c83eebc22 100644
--- a/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.ts
+++ b/airbyte-webapp/src/views/Connection/ConnectionForm/calculateInitialCatalog.ts
@@ -1,5 +1,10 @@
 import { SyncSchema, SyncSchemaStream } from "core/domain/catalog";
-import { DestinationSyncMode, SyncMode, AirbyteStreamConfiguration } from "core/request/AirbyteClient";
+import {
+  DestinationSyncMode,
+  SyncMode,
+  AirbyteStreamConfiguration,
+  StreamDescriptor,
+} from "core/request/AirbyteClient";
 
 const getDefaultCursorField = (streamNode: SyncSchemaStream): string[] => {
   if (streamNode.stream?.defaultCursorField?.length) {
@@ -119,18 +124,24 @@ const getOptimalSyncMode = (
 const calculateInitialCatalog = (
   schema: SyncSchema,
   supportedDestinationSyncModes: DestinationSyncMode[],
-  isNotCreateMode?: boolean
-): SyncSchema => ({
-  streams: schema.streams.map<SyncSchemaStream>((apiNode, id) => {
-    const nodeWithId: SyncSchemaStream = { ...apiNode, id: id.toString() };
-    const nodeStream = verifySourceDefinedProperties(verifySupportedSyncModes(nodeWithId), isNotCreateMode || false);
-
-    if (isNotCreateMode) {
-      return nodeStream;
-    }
-
-    return getOptimalSyncMode(verifyConfigCursorField(nodeStream), supportedDestinationSyncModes);
-  }),
-});
+  isNotCreateMode?: boolean,
+  newStreamDescriptors?: StreamDescriptor[]
+): SyncSchema => {
+  return {
+    streams: schema.streams.map<SyncSchemaStream>((apiNode, id) => {
+      const nodeWithId: SyncSchemaStream = { ...apiNode, id: id.toString() };
+      const nodeStream = verifySourceDefinedProperties(verifySupportedSyncModes(nodeWithId), isNotCreateMode || false);
+
+      // if the stream is new since a refresh, we want to verify cursor and get optimal sync modes
+      const matches = newStreamDescriptors?.some(
+        (streamId) => streamId.name === nodeStream?.stream?.name && streamId.namespace === nodeStream.stream?.namespace
+      );
+      if (isNotCreateMode && !matches) {
+        return nodeStream;
+      }
+      return getOptimalSyncMode(verifyConfigCursorField(nodeStream), supportedDestinationSyncModes);
+    }),
+  };
+};
 
 export default calculateInitialCatalog;
diff --git a/airbyte-webapp/src/views/Connection/ConnectionForm/formConfig.tsx b/airbyte-webapp/src/views/Connection/ConnectionForm/formConfig.tsx
index 996988201b41..8c0ef5da8cb5 100644
--- a/airbyte-webapp/src/views/Connection/ConnectionForm/formConfig.tsx
+++ b/airbyte-webapp/src/views/Connection/ConnectionForm/formConfig.tsx
@@ -252,14 +252,21 @@ export const useInitialValues = (
   destDefinition: DestinationDefinitionSpecificationRead,
   isNotCreateMode?: boolean
 ): FormikConnectionFormValues => {
+  const { catalogDiff } = connection;
+
+  const newStreamDescriptors = catalogDiff?.transforms
+    .filter((transform) => transform.transformType === "add_stream")
+    .map((stream) => stream.streamDescriptor);
+
   const initialSchema = useMemo(
     () =>
       calculateInitialCatalog(
         connection.syncCatalog,
         destDefinition?.supportedDestinationSyncModes || [],
-        isNotCreateMode
+        isNotCreateMode,
+        newStreamDescriptors
       ),
-    [connection.syncCatalog, destDefinition, isNotCreateMode]
+    [connection.syncCatalog, destDefinition?.supportedDestinationSyncModes, isNotCreateMode, newStreamDescriptors]
   );
 
   return useMemo(() => {