Cemaes Bay is a popular sandy beach at the mouth of the river Wygyr with a small harbour at the southern corner. The main beach (Traeth Mawr) lies east of the harbour and is backed by a sea wall and promenade. Traeth Bach is to the north-west of the harbour and is a smaller beach of sand and rocks. The main car park at the harbour is attended, but there is a further (free) car park at the northern end of the beach, as well as plenty of roadside parking. Pebbles to be found here include quartz, purple jasper and quartzite. Dog restrictions apply from 1st May until 30th September on Traeth Mawr and a Beach Warden is in attendance from late May until early September. Dogs are allowed on Traeth Bach beach.
Facilities include (seasonal) toilets, cycle parking and drinking water. The village centre is a short walk away, and has a few cafes, shops and pubs.
A recent and slightly controversial addition to the beach is St Patrick's bell - one of several around the country - which is designed to toll on the high tide. The name Cemaes originates from the Welsh 'cemais', meaning 'sea inlet'.