Trearddur Bay, Anglesey, Wales, is known locally, in Welsh, as Bae Trearddur, Ynys Mon, Cymru.

Trearddur¹ Bay is where the middle class of Holyhead, or Caergybi, tend to live. Situated just south of Holyhead on Holy Island, or Ynys Gybi, Trearddur Bay is a natural harbour with a gently sloping, sandy beach. Although there are nicer beaches in the area - Valley, for example² - Trearddur is worth visiting and has a variety of nice restaurants, good beach shops, and a lifeboat which is launched using a waterproofed Ford County tractor, an event which seems to be considered the height of excitement by the area's visiting and indigenous small boys. Another attraction of the bay is its rock pools, of the type usually only found in Enid Blyton books - full of crabs, starfish and shrimp just waiting to be hauled out with a child's fishing net. Sometimes, some impressively large crab - and even the occasional lobster - can be enticed out with a fish head on a ledger line.

The weather around Trearddur Bay is usually mild, as the sea is warmed by the Gulf stream and the worst storms exhaust themselves on the mountains of Snowdonia, so it's a great place for family holidays.