diff --git a/Dockerfile b/Dockerfile
index d9eb986295..b0fe584921 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -20,6 +20,9 @@ RUN poetry config virtualenvs.create false \
 # Build and install the package
 RUN pip install dist/*.whl
 
+# pandas is imported lazily by the CDK, so verify it is importable at build time
+RUN python -c "import pandas"
+
 # Recreate the original structure
 RUN mkdir -p source_declarative_manifest \
     && echo 'from source_declarative_manifest.run import run\n\nif __name__ == "__main__":\n    run()' > main.py \
diff --git a/airbyte_cdk/sources/declarative/extractors/response_to_file_extractor.py b/airbyte_cdk/sources/declarative/extractors/response_to_file_extractor.py
index f9a655db0c..145885e14c 100644
--- a/airbyte_cdk/sources/declarative/extractors/response_to_file_extractor.py
+++ b/airbyte_cdk/sources/declarative/extractors/response_to_file_extractor.py
@@ -10,7 +10,6 @@
 from math import nan
 from typing import Any, Dict, Iterable, Mapping, Optional, Tuple
 
-import pandas as pd
 import requests
 
 from airbyte_cdk.sources.declarative.extractors.record_extractor import RecordExtractor
@@ -139,6 +138,13 @@ def _read_with_chunks(
             ValueError: If an IO/Error occurs while reading the temporary data.
         """
 
+        # Imported lazily: pandas (and numpy) are slow to import and only needed for CSV parsing.
+        try:
+            import pandas as pd
+        except ImportError:
+            os.remove(path)
+            raise
+
         try:
             with open(path, "r", encoding=file_encoding) as data:
                 # When preserving NA values, disable pandas' default NA parsing so strings like "NA"/"N/A" are kept as-is,
diff --git a/unit_tests/source_declarative_manifest/test_source_declarative_manifest_imports.py b/unit_tests/source_declarative_manifest/test_source_declarative_manifest_imports.py
new file mode 100644
index 0000000000..d916e7a5a2
--- /dev/null
+++ b/unit_tests/source_declarative_manifest/test_source_declarative_manifest_imports.py
@@ -0,0 +1,70 @@
+# Copyright (c) 2026 Airbyte, Inc., all rights reserved.
+
+import json
+import subprocess
+import sys
+from pathlib import Path
+
+SCRIPT = """
+import json
+import sys
+from unittest.mock import patch
+
+import requests_mock
+import yaml
+
+from airbyte_cdk.cli.source_declarative_manifest import _run
+
+manifest_path, config_path = sys.argv[1:]
+with open(manifest_path) as manifest_file:
+    manifest = yaml.safe_load(manifest_file)
+
+with patch(
+    "airbyte_cdk.cli.source_declarative_manifest._run._is_local_manifest_command",
+    return_value=True,
+):
+    with patch(
+        "airbyte_cdk.cli.source_declarative_manifest._run.YamlDeclarativeSource._read_and_parse_yaml_file",
+        return_value=manifest,
+    ):
+        with requests_mock.Mocker() as mocker:
+            mocker.get(
+                "https://pokeapi.co/api/v2/pokemon/blastoise",
+                json={"name": "blastoise"},
+            )
+            _run.handle_command(["spec"])
+            _run.handle_command(["check", "--config", config_path])
+            _run.handle_command(["discover", "--config", config_path])
+
+print("LOADED_HEAVY_MODULES=" + json.dumps(sorted(m for m in ("pandas", "numpy") if m in sys.modules)))
+"""
+
+
+def test_spec_check_discover_do_not_import_pandas_or_numpy(
+    valid_local_manifest, valid_local_config_file
+) -> None:
+    """Declarative/SDM start-up must not import pandas or numpy. Import heavy libraries inside the function that needs them; `python -X importtime -c "import airbyte_cdk.cli.source_declarative_manifest._run"` shows which module pulls one in."""
+    result = subprocess.run(
+        [
+            sys.executable,
+            "-c",
+            SCRIPT,
+            str(valid_local_manifest),
+            str(valid_local_config_file),
+        ],
+        capture_output=True,
+        text=True,
+        timeout=120,
+        cwd=Path(__file__).resolve().parents[2],
+    )
+
+    output = f"stdout:\n{result.stdout}\nstderr:\n{result.stderr}"
+    assert result.returncode == 0, output
+    assert '"connectionStatus":{"status":"SUCCEEDED"}' in result.stdout, output
+    assert '"catalog"' in result.stdout, output
+    marker = next(
+        (line for line in result.stdout.splitlines() if line.startswith("LOADED_HEAVY_MODULES=")),
+        None,
+    )
+    assert marker is not None, output
+    assert json.loads(marker.split("=", 1)[1]) == [], output
diff --git a/unit_tests/sources/declarative/extractors/test_response_to_file_extractor.py b/unit_tests/sources/declarative/extractors/test_response_to_file_extractor.py
index 6294db49d8..314788b4de 100644
--- a/unit_tests/sources/declarative/extractors/test_response_to_file_extractor.py
+++ b/unit_tests/sources/declarative/extractors/test_response_to_file_extractor.py
@@ -5,6 +5,7 @@
 from pathlib import Path
 from unittest import TestCase
 
+import pandas  # noqa: F401  # loaded here so limit_memory measures CSV parsing, not the extractor's lazy import
 import pytest
 import requests
 import requests_mock