diff --git a/cwms/timeseries/timeseries.py b/cwms/timeseries/timeseries.py
index 17a32947..9ce3dfec 100644
--- a/cwms/timeseries/timeseries.py
+++ b/cwms/timeseries/timeseries.py
@@ -166,6 +166,9 @@ def _call_with_retry(fn: Any, *args: Any, attempts: int = _CHUNK_ATTEMPTS) -> An
         try:
             return fn(*args)
         except Exception as e:
+            status_code = getattr(getattr(e, "response", None), "status_code", None)
+            if status_code == 404:
+                raise
             if i == attempts - 1:
                 raise
             logging.warning(f"chunk attempt {i + 1}/{attempts} failed: {e}")
diff --git a/tests/cda/timeseries/timeseries_CDA_test.py b/tests/cda/timeseries/timeseries_CDA_test.py
index 83abc050..4e8a8c92 100644
--- a/tests/cda/timeseries/timeseries_CDA_test.py
+++ b/tests/cda/timeseries/timeseries_CDA_test.py
@@ -22,6 +22,7 @@
 TEST_TSID_COPY_NULLS = f"{TEST_LOCATION_ID}.Stage.Inst.15Minutes.0.Raw-Copy-Nulls"
 TS_ID_REV_TEST = TEST_TSID_MULTI.replace("Raw-Multi", "Raw-Rev-Test")
 TEST_TSID_CHUNK_PARTIAL = f"{TEST_LOCATION_ID}.Stage.Inst.15Minutes.0.Raw-Multi-Partial"
+TEST_TSID_MISSING = f"{TEST_LOCATION_ID}.Stage.Inst.15Minutes.0.Raw-Missing-404"
 # Generate 15-minute interval timestamps
 START_DATE_CHUNK_MULTI = datetime(2025, 7, 31, 0, 0, tzinfo=timezone.utc)
 END_DATE_CHUNK_MULTI = datetime(2025, 9, 30, 23, 45, tzinfo=timezone.utc)
@@ -37,6 +38,7 @@
     TEST_TSID_CHUNK_NULLS,
     TEST_TSID_COPY_NULLS,
     TEST_TSID_CHUNK_PARTIAL,
+    TEST_TSID_MISSING,
     TEST_TSID_DELETE,
 ]
 
@@ -390,6 +392,33 @@ def sabotaged(selector, endpoint, param, begin, end):
     assert "simulated CDA failure" in error_msg
 
 
+def test_get_timeseries_missing_chunk_404_real_api():
+    """A missing time series should fail once with a 404, not retry."""
+
+    max_days = 14
+    chunks = ts.chunk_timeseries_time_range(
+        START_DATE_CHUNK_MULTI,
+        END_DATE_CHUNK_MULTI.replace(tzinfo=timezone.utc),
+        timedelta(days=max_days),
+    )
+    assert len(chunks) > 1, "Test requires multiple chunks to exercise retry scope"
+
+    with pytest.raises(RuntimeError) as exc_info:
+        ts.get_timeseries(
+            ts_id=TEST_TSID_MISSING,
+            office_id=TEST_OFFICE,
+            begin=START_DATE_CHUNK_MULTI,
+            end=END_DATE_CHUNK_MULTI,
+            max_days_per_chunk=max_days,
+            unit="SI",
+        )
+
+    error_msg = str(exc_info.value)
+    assert "chunk(s) failed to fetch" in error_msg
+    assert "Failed to fetch data from" in error_msg
+    assert "Not Found" in error_msg or "404" in error_msg
+
+
 def test_store_timesereis_chunk_to_with_null_values():
     # Define parameters
     ts_id = TEST_TSID_CHUNK_NULLS
diff --git a/tests/mock/timeseries/timeseries_test.py b/tests/mock/timeseries/timeseries_test.py
index 03e64c91..e5c906b7 100644
--- a/tests/mock/timeseries/timeseries_test.py
+++ b/tests/mock/timeseries/timeseries_test.py
@@ -251,6 +251,27 @@ def test_get_timeseries_paging(requests_mock):
     assert data.df.shape == (30, 3)
 
 
+def test_call_with_retry_does_not_retry_404():
+    class ResponseStub:
+        url = "https://mockwebserver.cwms.gov/timeseries"
+        status_code = 404
+        reason = "Not Found"
+        content = b""
+
+    call_count = 0
+
+    def failing_call():
+        nonlocal call_count
+        call_count += 1
+        raise cwms.api.ApiError(ResponseStub())
+
+    with pytest.raises(cwms.api.ApiError) as exc_info:
+        timeseries._call_with_retry(failing_call)
+
+    assert exc_info.value.response.status_code == 404
+    assert call_count == 1
+
+
 def test_get_timeseries_group_default(requests_mock):
     group_id = "USGS TS Data Acquisition"
     category_id = "Data Acquisition"