diff --git a/csp/impl/wiring/signature.py b/csp/impl/wiring/signature.py
index db52fcad..a2f481e7 100644
--- a/csp/impl/wiring/signature.py
+++ b/csp/impl/wiring/signature.py
@@ -12,7 +12,7 @@
 from csp.impl.wiring.outputs import OutputsContainer
 from csp.impl.wiring.special_output_names import UNNAMED_OUTPUT_NAME
 
-USE_PYDANTIC: bool = os.environ.get("CSP_PYDANTIC")
+USE_PYDANTIC: bool = os.environ.get("CSP_PYDANTIC", True)
 
 if USE_PYDANTIC:
     from pydantic import (
diff --git a/csp/tests/test_engine.py b/csp/tests/test_engine.py
index cd481fd1..09d21697 100644
--- a/csp/tests/test_engine.py
+++ b/csp/tests/test_engine.py
@@ -21,7 +21,7 @@
 from csp.impl.wiring.runtime import build_graph
 from csp.lib import _csptestlibimpl
 
-USE_PYDANTIC = os.environ.get("CSP_PYDANTIC")
+USE_PYDANTIC = os.environ.get("CSP_PYDANTIC", True)
 
 
 @csp.graph
diff --git a/csp/tests/test_type_checking.py b/csp/tests/test_type_checking.py
index 06acd1a1..87f93089 100644
--- a/csp/tests/test_type_checking.py
+++ b/csp/tests/test_type_checking.py
@@ -13,7 +13,7 @@
 from csp.impl.types.typing_utils import CspTypingUtils
 from csp.impl.wiring.runtime import build_graph
 
-USE_PYDANTIC = os.environ.get("CSP_PYDANTIC")
+USE_PYDANTIC = os.environ.get("CSP_PYDANTIC", True)
 
 
 class TestTypeChecking(unittest.TestCase):