diff --git a/pytransform3d/rotations/__init__.py b/pytransform3d/rotations/__init__.py
index 59dc7bc49..539f4afa9 100644
--- a/pytransform3d/rotations/__init__.py
+++ b/pytransform3d/rotations/__init__.py
@@ -9,11 +9,14 @@
     vector_projection, perpendicular_to_vectors,
     norm_axis_angle, norm_compact_axis_angle, norm_matrix,
     plane_basis_from_normal,
-    random_vector, random_axis_angle, random_compact_axis_angle,
-    random_quaternion,
     check_skew_symmetric_matrix, check_matrix, check_quaternion,
     check_quaternions, check_axis_angle, check_compact_axis_angle,
     check_rotor, check_mrp)
+from ._random import (
+    random_vector,
+    random_axis_angle,
+    random_compact_axis_angle,
+    random_quaternion)
 from ._conversions import (
     quaternion_from_axis_angle, quaternion_from_compact_axis_angle,
     quaternion_from_matrix, quaternion_wxyz_from_xyzw,
diff --git a/pytransform3d/rotations/_random.py b/pytransform3d/rotations/_random.py
new file mode 100644
index 000000000..fd44cc244
--- /dev/null
+++ b/pytransform3d/rotations/_random.py
@@ -0,0 +1,86 @@
+import numpy as np
+
+from ._utils import norm_vector
+
+
+def random_vector(rng=np.random.default_rng(0), n=3):
+    r"""Generate an nd vector with normally distributed components.
+
+    Each component will be sampled from :math:`\mathcal{N}(\mu=0, \sigma=1)`.
+
+    Parameters
+    ----------
+    rng : np.random.Generator, optional (default: random seed 0)
+        Random number generator
+
+    n : int, optional (default: 3)
+        Number of vector components
+
+    Returns
+    -------
+    v : array, shape (n,)
+        Random vector
+    """
+    return rng.standard_normal(size=n)
+
+
+def random_axis_angle(rng=np.random.default_rng(0)):
+    r"""Generate random axis-angle.
+
+    The angle will be sampled uniformly from the interval :math:`[0, \pi)`
+    and each component of the rotation axis will be sampled from
+    :math:`\mathcal{N}(\mu=0, \sigma=1)` and then the axis will be normalized
+    to length 1.
+
+    Parameters
+    ----------
+    rng : np.random.Generator, optional (default: random seed 0)
+        Random number generator
+
+    Returns
+    -------
+    a : array, shape (4,)
+        Axis of rotation and rotation angle: (x, y, z, angle)
+    """
+    angle = np.pi * rng.random()
+    a = np.array([0, 0, 0, angle])
+    a[:3] = norm_vector(rng.standard_normal(size=3))
+    return a
+
+
+def random_compact_axis_angle(rng=np.random.default_rng(0)):
+    r"""Generate random compact axis-angle.
+
+    The angle will be sampled uniformly from the interval :math:`[0, \pi)`
+    and each component of the rotation axis will be sampled from
+    :math:`\mathcal{N}(\mu=0, \sigma=1)` and then the axis will be normalized
+    to length 1.
+
+    Parameters
+    ----------
+    rng : np.random.Generator, optional (default: random seed 0)
+        Random number generator
+
+    Returns
+    -------
+    a : array, shape (3,)
+        Axis of rotation and rotation angle: angle * (x, y, z)
+    """
+    a = random_axis_angle(rng)
+    return a[:3] * a[3]
+
+
+def random_quaternion(rng=np.random.default_rng(0)):
+    """Generate random quaternion.
+
+    Parameters
+    ----------
+    rng : np.random.Generator, optional (default: random seed 0)
+        Random number generator
+
+    Returns
+    -------
+    q : array, shape (4,)
+        Unit quaternion to represent rotation: (w, x, y, z)
+    """
+    return norm_vector(rng.standard_normal(size=4))
diff --git a/pytransform3d/rotations/_random.pyi b/pytransform3d/rotations/_random.pyi
new file mode 100644
index 000000000..59df9af25
--- /dev/null
+++ b/pytransform3d/rotations/_random.pyi
@@ -0,0 +1,14 @@
+import numpy as np
+import numpy.typing as npt
+
+
+def random_vector(rng: np.random.Generator = ..., n: int = ...) -> np.ndarray: ...
+
+
+def random_axis_angle(rng: np.random.Generator = ...) -> np.ndarray: ...
+
+
+def random_compact_axis_angle(rng: np.random.Generator = ...) -> np.ndarray: ...
+
+
+def random_quaternion(rng: np.random.Generator = ...) -> np.ndarray: ...
diff --git a/pytransform3d/rotations/_utils.py b/pytransform3d/rotations/_utils.py
index 815ff4cb4..ac3a4a95d 100644
--- a/pytransform3d/rotations/_utils.py
+++ b/pytransform3d/rotations/_utils.py
@@ -293,89 +293,6 @@ def plane_basis_from_normal(plane_normal):
     return x_axis, y_axis
 
 
-def random_vector(rng=np.random.default_rng(0), n=3):
-    r"""Generate an nd vector with normally distributed components.
-
-    Each component will be sampled from :math:`\mathcal{N}(\mu=0, \sigma=1)`.
-
-    Parameters
-    ----------
-    rng : np.random.Generator, optional (default: random seed 0)
-        Random number generator
-
-    n : int, optional (default: 3)
-        Number of vector components
-
-    Returns
-    -------
-    v : array, shape (n,)
-        Random vector
-    """
-    return rng.standard_normal(size=n)
-
-
-def random_axis_angle(rng=np.random.default_rng(0)):
-    r"""Generate random axis-angle.
-
-    The angle will be sampled uniformly from the interval :math:`[0, \pi)`
-    and each component of the rotation axis will be sampled from
-    :math:`\mathcal{N}(\mu=0, \sigma=1)` and then the axis will be normalized
-    to length 1.
-
-    Parameters
-    ----------
-    rng : np.random.Generator, optional (default: random seed 0)
-        Random number generator
-
-    Returns
-    -------
-    a : array, shape (4,)
-        Axis of rotation and rotation angle: (x, y, z, angle)
-    """
-    angle = np.pi * rng.random()
-    a = np.array([0, 0, 0, angle])
-    a[:3] = norm_vector(rng.standard_normal(size=3))
-    return a
-
-
-def random_compact_axis_angle(rng=np.random.default_rng(0)):
-    r"""Generate random compact axis-angle.
-
-    The angle will be sampled uniformly from the interval :math:`[0, \pi)`
-    and each component of the rotation axis will be sampled from
-    :math:`\mathcal{N}(\mu=0, \sigma=1)` and then the axis will be normalized
-    to length 1.
-
-    Parameters
-    ----------
-    rng : np.random.Generator, optional (default: random seed 0)
-        Random number generator
-
-    Returns
-    -------
-    a : array, shape (3,)
-        Axis of rotation and rotation angle: angle * (x, y, z)
-    """
-    a = random_axis_angle(rng)
-    return a[:3] * a[3]
-
-
-def random_quaternion(rng=np.random.default_rng(0)):
-    """Generate random quaternion.
-
-    Parameters
-    ----------
-    rng : np.random.Generator, optional (default: random seed 0)
-        Random number generator
-
-    Returns
-    -------
-    q : array, shape (4,)
-        Unit quaternion to represent rotation: (w, x, y, z)
-    """
-    return norm_vector(rng.standard_normal(size=4))
-
-
 def check_skew_symmetric_matrix(V, tolerance=1e-6, strict_check=True):
     """Input validation of a skew-symmetric matrix.
 
diff --git a/pytransform3d/rotations/_utils.pyi b/pytransform3d/rotations/_utils.pyi
index f4dfb8923..be099814d 100644
--- a/pytransform3d/rotations/_utils.pyi
+++ b/pytransform3d/rotations/_utils.pyi
@@ -34,19 +34,6 @@ def plane_basis_from_normal(
         plane_normal: npt.ArrayLike) -> Tuple[np.ndarray, np.ndarray]: ...
 
 
-
-def random_vector(rng: np.random.Generator = ..., n: int = ...) -> np.ndarray: ...
-
-
-def random_axis_angle(rng: np.random.Generator = ...) -> np.ndarray: ...
-
-
-def random_compact_axis_angle(rng: np.random.Generator = ...) -> np.ndarray: ...
-
-
-def random_quaternion(rng: np.random.Generator = ...) -> np.ndarray: ...
-
-
 def check_skew_symmetric_matrix(V: npt.ArrayLike, tolerance: float = ..., strict_check: bool = ...) -> np.ndarray: ...