diff --git a/.changeset/python-timeout-zero.md b/.changeset/python-timeout-zero.md
new file mode 100644
index 0000000000..62bb6c9491
--- /dev/null
+++ b/.changeset/python-timeout-zero.md
@@ -0,0 +1,5 @@
+---
+'@e2b/python-sdk': patch
+---
+
+Keep an explicit `timeout=0` on sandbox create and connect instead of substituting the 300s default.
diff --git a/packages/python-sdk/e2b/sandbox_async/main.py b/packages/python-sdk/e2b/sandbox_async/main.py
index 7b1d7253d0..d037b5e7a5 100644
--- a/packages/python-sdk/e2b/sandbox_async/main.py
+++ b/packages/python-sdk/e2b/sandbox_async/main.py
@@ -1158,7 +1158,9 @@ async def _create(
         else:
             response = await SandboxApi._create_sandbox(
                 template=template or cls.default_template,
-                timeout=timeout or cls.default_sandbox_timeout,
+                timeout=(
+                    timeout if timeout is not None else cls.default_sandbox_timeout
+                ),
                 metadata=metadata,
                 env_vars=envs,
                 secure=secure,
diff --git a/packages/python-sdk/e2b/sandbox_async/sandbox_api.py b/packages/python-sdk/e2b/sandbox_async/sandbox_api.py
index b4171327f3..3a7f78f88b 100644
--- a/packages/python-sdk/e2b/sandbox_async/sandbox_api.py
+++ b/packages/python-sdk/e2b/sandbox_async/sandbox_api.py
@@ -531,7 +531,9 @@ async def _cls_connect(
         on_resume: SandboxOnResume = "restore",
         **opts: Unpack[ApiParams],
     ) -> SandboxCreateResponse:
-        timeout = timeout or SandboxBase.default_sandbox_timeout
+        timeout = (
+            timeout if timeout is not None else SandboxBase.default_sandbox_timeout
+        )
 
         # Sandbox is not running, resume it
         config = ConnectionConfig(logger=logger, **cls._resolve_api_params(**opts))
diff --git a/packages/python-sdk/e2b/sandbox_sync/main.py b/packages/python-sdk/e2b/sandbox_sync/main.py
index 80b4ff1e97..0be427834c 100644
--- a/packages/python-sdk/e2b/sandbox_sync/main.py
+++ b/packages/python-sdk/e2b/sandbox_sync/main.py
@@ -1154,7 +1154,9 @@ def _create(
         else:
             response = SandboxApi._create_sandbox(
                 template=template or cls.default_template,
-                timeout=timeout or cls.default_sandbox_timeout,
+                timeout=(
+                    timeout if timeout is not None else cls.default_sandbox_timeout
+                ),
                 metadata=metadata,
                 env_vars=envs,
                 secure=secure,
diff --git a/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py b/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py
index d0d9d1656b..1d18694d34 100644
--- a/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py
+++ b/packages/python-sdk/e2b/sandbox_sync/sandbox_api.py
@@ -346,7 +346,9 @@ def _cls_connect(
         on_resume: SandboxOnResume = "restore",
         **opts: Unpack[ApiParams],
     ) -> SandboxCreateResponse:
-        timeout = timeout or SandboxBase.default_sandbox_timeout
+        timeout = (
+            timeout if timeout is not None else SandboxBase.default_sandbox_timeout
+        )
 
         config = ConnectionConfig(logger=logger, **cls._resolve_api_params(**opts))
 
diff --git a/packages/python-sdk/tests/shared/sandbox/test_timeout.py b/packages/python-sdk/tests/shared/sandbox/test_timeout.py
new file mode 100644
index 0000000000..3c394e5c47
--- /dev/null
+++ b/packages/python-sdk/tests/shared/sandbox/test_timeout.py
@@ -0,0 +1,83 @@
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, Mock
+
+from e2b import AsyncSandbox, Sandbox
+from e2b.api.client.api.sandboxes import (
+    post_sandboxes,
+    post_sandboxes_sandbox_id_connect,
+)
+from e2b.api.client.models import Sandbox as SandboxModel
+from e2b.sandbox.main import SandboxBase
+
+
+def _created_sandbox():
+    return SimpleNamespace(
+        status_code=200,
+        parsed=SandboxModel(
+            client_id="client-id",
+            envd_version="0.2.4",
+            sandbox_id="sbx-test",
+            template_id="template-id",
+        ),
+    )
+
+
+def test_create_sends_timeout_zero(monkeypatch, test_api_key):
+    # timeout=0 is a value. `timeout or default` used to send 300 instead.
+    request = Mock(return_value=_created_sandbox())
+    monkeypatch.setattr(post_sandboxes, "sync_detailed", request)
+
+    Sandbox.create(api_key=test_api_key, timeout=0)
+
+    assert request.call_args.kwargs["body"].to_dict()["timeout"] == 0
+
+
+def test_create_omitted_timeout_uses_default(monkeypatch, test_api_key):
+    request = Mock(return_value=_created_sandbox())
+    monkeypatch.setattr(post_sandboxes, "sync_detailed", request)
+
+    Sandbox.create(api_key=test_api_key)
+
+    assert (
+        request.call_args.kwargs["body"].to_dict()["timeout"]
+        == SandboxBase.default_sandbox_timeout
+    )
+
+
+async def test_async_create_sends_timeout_zero(monkeypatch, test_api_key):
+    request = AsyncMock(return_value=_created_sandbox())
+    monkeypatch.setattr(post_sandboxes, "asyncio_detailed", request)
+
+    await AsyncSandbox.create(api_key=test_api_key, timeout=0)
+
+    assert request.call_args.kwargs["body"].to_dict()["timeout"] == 0
+
+
+async def test_async_create_omitted_timeout_uses_default(monkeypatch, test_api_key):
+    request = AsyncMock(return_value=_created_sandbox())
+    monkeypatch.setattr(post_sandboxes, "asyncio_detailed", request)
+
+    await AsyncSandbox.create(api_key=test_api_key)
+
+    assert (
+        request.call_args.kwargs["body"].to_dict()["timeout"]
+        == SandboxBase.default_sandbox_timeout
+    )
+
+
+def test_connect_sends_timeout_zero(monkeypatch, test_api_key):
+    request = Mock(return_value=_created_sandbox())
+    monkeypatch.setattr(post_sandboxes_sandbox_id_connect, "sync_detailed", request)
+
+    Sandbox.connect("sbx-test", timeout=0, api_key=test_api_key)
+
+    assert request.call_args.kwargs["body"].to_dict()["timeout"] == 0
+
+
+async def test_async_connect_sends_timeout_zero(monkeypatch, test_api_key):
+    request = AsyncMock(return_value=_created_sandbox())
+    monkeypatch.setattr(post_sandboxes_sandbox_id_connect, "asyncio_detailed", request)
+
+    await AsyncSandbox.connect("sbx-test", timeout=0, api_key=test_api_key)
+
+    assert request.call_args.kwargs["body"].to_dict()["timeout"] == 0