100 Egg Mud Bath is one of Nha Trang's more playful spa attractions, built around private mud baths, mineral pools, and an egg-shaped design theme. It is unabashedly touristy, but mud bathing is a familiar part of the city's leisure circuit.
Go when you want a relaxed half day rather than culture or beach time. It is outside the centre, so check transport and current packages before committing.