The Postal Museum occupies the General Post Office on the harbour side of the city — a handsome stone building from 1868. The displays cover the history of the post on Mauritius from the early 1770s, with old uniforms, pillar boxes, a working telegraph machine, and copies of the famous Blue and Red Penny stamps.
It's a small museum and a quiet hour. Entry is around Rs 150. Good combined with the nearby Aapravasi Ghat, which is a five-minute walk.