diff --git a/src/diffusion/augmentation.py b/src/diffusion/augmentation.py
index 8e9a23c..21138eb 100644
--- a/src/diffusion/augmentation.py
+++ b/src/diffusion/augmentation.py
@@ -1,16 +1,43 @@
 """Data augmentations applied prior to sampling from the diffusion trajectory."""
-
 import torch
+from src.utils.geometry.vector import Vec3Array
+from src.utils.geometry.rotation_matrix import Rot3Array
 
 
 def centre_random_augmentation(
-        atom_positions: torch.Tensor,  # (bs, n_atoms, 3)
+        atom_positions: Vec3Array,  # (bs, n_atoms)
         s_trans: float = 1.0,  # Translation scaling factor
-) -> torch.Tensor:
-    """Centers the atoms and applies random rotation and translation."""
+) -> Vec3Array:  # (bs, n_atoms)
+    """Centers the atoms and applies random rotation and translation.
+    Args:
+        atom_positions:
+            [*, n_atoms] vector of atom coordinates.
+        s_trans:
+            Scaling factor in Angstroms for the random translation sampled
+            from a normal distribution.
+    Returns:
+        [*, n_atoms] vector of atom coordinates after augmentation.
+    """
+    batch_size, n_atoms = atom_positions.shape
+    device = atom_positions.x.device
+
     # Center the atoms
+    center = atom_positions.mean(dim=-2, keepdim=True)
+    atom_positions = atom_positions - center
 
     # Sample random rotation
+    quaternions = torch.randn(batch_size, 4, device=device)
+    rots = Rot3Array.from_quaternion(w=quaternions[:, 0],
+                                     x=quaternions[:, 1],
+                                     y=quaternions[:, 2],
+                                     z=quaternions[:, 3],
+                                     normalize=True)  # (bs)
+    rots = rots.unsqueeze(-1)  # (bs, 1)
+
+    # Sample random translation
+    trans = s_trans * Vec3Array.from_array(torch.randn((batch_size, 3), device=device))
+    trans = trans.unsqueeze(-1)  # (bs, 1)
 
     # Apply
-    pass
+    atom_positions = rots.apply_to_point(atom_positions) + trans
+    return atom_positions
diff --git a/src/diffusion/conditioning.py b/src/diffusion/conditioning.py
index 1ebfec4..78448b8 100644
--- a/src/diffusion/conditioning.py
+++ b/src/diffusion/conditioning.py
@@ -102,5 +102,3 @@ def encode(feature_tensor: torch.Tensor,
             torch.full_like(relative_dists, 2*clamp_max + 1)
         )
         return F.one_hot(d_ij, num_classes=2 * clamp_max + 2)  # (bs, n_tokens, n_tokens, 2 * clamp_max + 2)
-
-
diff --git a/src/utils/geometry/vector.py b/src/utils/geometry/vector.py
index 99bdefe..c19d199 100644
--- a/src/utils/geometry/vector.py
+++ b/src/utils/geometry/vector.py
@@ -120,11 +120,18 @@ def reshape(self, new_shape) -> Vec3Array:
 
         return Vec3Array(x, y, z)
 
-    def sum(self, dim: int) -> Vec3Array:
+    def sum(self, dim: int, keepdim=False) -> Vec3Array:
         return Vec3Array(
-            torch.sum(self.x, dim=dim),
-            torch.sum(self.y, dim=dim),
-            torch.sum(self.z, dim=dim),
+            torch.sum(self.x, dim=dim, keepdim=keepdim),
+            torch.sum(self.y, dim=dim, keepdim=keepdim),
+            torch.sum(self.z, dim=dim, keepdim=keepdim),
+        )
+
+    def mean(self, dim: int, keepdim=False) -> Vec3Array:
+        return Vec3Array(
+            torch.mean(self.x, dim=dim, keepdim=keepdim),
+            torch.mean(self.y, dim=dim, keepdim=keepdim),
+            torch.mean(self.z, dim=dim, keepdim=keepdim),
         )
 
     def unsqueeze(self, dim: int):
diff --git a/tests/test_augmentation.py b/tests/test_augmentation.py
new file mode 100644
index 0000000..5c4dbce
--- /dev/null
+++ b/tests/test_augmentation.py
@@ -0,0 +1,33 @@
+import unittest
+import torch
+from src.utils.geometry.vector import Vec3Array
+from src.utils.geometry.rotation_matrix import Rot3Array
+from src.diffusion.augmentation import centre_random_augmentation
+
+
+class TestCentreRandomAugmentation(unittest.TestCase):
+    def setUp(self):
+        self.batch_size = 2
+        self.n_atoms = 5
+        atom_positions = torch.randn(self.batch_size, self.n_atoms, 3)
+        self.atom_positions = Vec3Array(x=atom_positions[:, :, 0],
+                                        y=atom_positions[:, :, 1],
+                                        z=atom_positions[:, :, 2])
+
+    def test_output_shape(self):
+        augmented_positions = centre_random_augmentation(self.atom_positions)
+        self.assertEqual(augmented_positions.to_tensor().shape, (self.batch_size, self.n_atoms, 3))
+
+    def test_random_translation(self):
+        s_trans = 1.0
+        initial_positions = self.atom_positions.x.clone()
+        augmented_positions = centre_random_augmentation(self.atom_positions, s_trans=s_trans)
+        translation = augmented_positions.x - initial_positions
+        translation_magnitudes = translation.norm(dim=-1)
+        self.assertTrue(torch.all(translation_magnitudes > 0))
+
+    def test_random_rotation(self):
+        initial_positions = self.atom_positions.x.clone()
+        augmented_positions = centre_random_augmentation(self.atom_positions)
+        rotation_diff = augmented_positions.x - initial_positions
+        self.assertFalse(torch.allclose(rotation_diff, torch.zeros_like(rotation_diff), atol=1e-6))