While they don’t take to the water with quite the same zest and reckless abandon as labradors do, and their size and build make it difficult for them to bob around in it, Bullmastiffs, just like all dogs, can swim. They might not like to do it very much, and it isn’t something that they’ll do very often, but they can swim.
And, even though they don’t enjoy it, when it comes to swimming, Bullmastiffs have a hidden weapon in their biological arsenal - webbed paws. Bullmastiffs’ webbed paws give them the extra edge that a dog their size needs to paddle around, and swim. So just because Bullmastiffs don’t swim, it doesn’t mean that they can’t swim. They can.