diff --git a/py-polars/polars/lazyframe/frame.py b/py-polars/polars/lazyframe/frame.py
index d78f4e45a6f2..5f615400267b 100644
--- a/py-polars/polars/lazyframe/frame.py
+++ b/py-polars/polars/lazyframe/frame.py
@@ -717,18 +717,18 @@ def serialize(
             msg = f"invalid serialization format: {format!r}"
             raise ValueError(msg)
 
-        def serialize_to_bytes() -> str:
+        def serialize_to_bytes() -> bytes:
             with BytesIO() as buf:
                 serializer(buf)
                 serialized = buf.getvalue()
             return serialized
 
         if file is None:
-            seralized = serialize_to_bytes()
+            serialized = serialize_to_bytes()
             if format == "json":
-                return seralized.decode()
+                return serialized.decode()
             else:
-                return seralized
+                return serialized
         elif isinstance(file, StringIO):
             serialized_str = serialize_to_bytes().decode()
             file.write(serialized_str)
diff --git a/py-polars/tests/unit/lazyframe/test_serde.py b/py-polars/tests/unit/lazyframe/test_serde.py
index bc1cd27e2020..8ff74d672491 100644
--- a/py-polars/tests/unit/lazyframe/test_serde.py
+++ b/py-polars/tests/unit/lazyframe/test_serde.py
@@ -14,6 +14,13 @@
     from pathlib import Path
 
 
+@given(lf=dataframes(lazy=True))
+def test_lf_serde_roundtrip_binary(lf: pl.LazyFrame) -> None:
+    serialized = lf.serialize(format="binary")
+    result = pl.LazyFrame.deserialize(io.BytesIO(serialized, format="binary"))
+    assert_frame_equal(result, lf, categorical_as_str=True)
+
+
 @given(
     lf=dataframes(
         lazy=True,
@@ -23,9 +30,9 @@
         ],
     )
 )
-def test_lf_serde_roundtrip(lf: pl.LazyFrame) -> None:
-    serialized = lf.serialize()
-    result = pl.LazyFrame.deserialize(io.StringIO(serialized))
+def test_lf_serde_roundtrip_json(lf: pl.LazyFrame) -> None:
+    serialized = lf.serialize(format="json")
+    result = pl.LazyFrame.deserialize(io.StringIO(serialized), format="json")
     assert_frame_equal(result, lf, categorical_as_str=True)
 
 
@@ -37,17 +44,30 @@ def lf() -> pl.LazyFrame:
 
 def test_lf_serde(lf: pl.LazyFrame) -> None:
     serialized = lf.serialize()
-    assert isinstance(serialized, str)
-    result = pl.LazyFrame.deserialize(io.StringIO(serialized))
+    assert isinstance(serialized, bytes)
+    result = pl.LazyFrame.deserialize(io.BytesIO(serialized))
+    assert_frame_equal(result, lf)
 
+
+def test_lf_serde_json_stringio(lf: pl.LazyFrame) -> None:
+    serialized = lf.serialize(format="json")
+    assert isinstance(serialized, str)
+    result = pl.LazyFrame.deserialize(io.StringIO(serialized), format="json")
     assert_frame_equal(result, lf)
 
 
-@pytest.mark.parametrize("buf", [io.BytesIO(), io.StringIO()])
-def test_lf_serde_to_from_buffer(lf: pl.LazyFrame, buf: io.IOBase) -> None:
-    lf.serialize(buf)
+@pytest.mark.parametrize(
+    ("format", "buf"),
+    [
+        ("binary", io.BytesIO()),
+        ("json", io.StringIO()),
+        ("json", io.BytesIO()),
+    ],
+)
+def test_lf_serde_to_from_buffer(lf: pl.LazyFrame, format: str, buf: io.IOBase) -> None:
+    lf.serialize(buf, format=format)
     buf.seek(0)
-    result = pl.LazyFrame.deserialize(buf)
+    result = pl.LazyFrame.deserialize(buf, format=format)
     assert_frame_equal(lf, result)
 
 
@@ -62,8 +82,8 @@ def test_lf_serde_to_from_file(lf: pl.LazyFrame, tmp_path: Path) -> None:
     assert_frame_equal(lf, result)
 
 
-def test_lazyframe_serde_json(lf: pl.LazyFrame) -> None:
-    serialized = lf.serialize(format="json")
-    assert isinstance(serialized, bytes)
-    result = pl.LazyFrame.deserialize(io.BytesIO(serialized), format="json")
+def test_lf_serde_enum_data() -> None:
+    lf = pl.LazyFrame({"a": ["a", "b", "a"]}, schema={"a": pl.Enum(["b", "a"])})
+    serialized = lf.serialize()
+    result = pl.LazyFrame.deserialize(io.BytesIO(serialized))
     assert_frame_equal(result, lf)