Newborough Forest is on the southernmost corner of Anglesey, and at 2,000 acres is one of the largest publicly accessible forests in Wales and one of the most important red squirrel conservation sites in the UK. A large area of saltmarsh and mudflats borders the forest to the north west and provides wintering grounds for various wading birds and wildfowl, while to the east of the forest is Newborough Warren, a large sand dune system which harbours many rare and interesting plants and is home to a population of great crested newts.
There's a network of footpaths across the warren and through the forest to the beach, and the forest itself has many cycling and horse riding trails. There's also a Trim Trail, a designated walking/jogging route through the forest with eleven exercise equipment stations along the way. There are three car parks on the outer fringes of the forest and warren and a fourth down by the beach - access to that one is via a toll road which runs through the forest and has a £3 charge, though it's well worth it if you want to avoid the very long walk.
The beach itself is huge, stretching from Abermenai Point on the Menai straits in the east, past the sand dunes of the warren and the forest right round to Llanddwyn Island; on a clear day the views of the Snowdonia hills on the mainland are fantastic. You can walk off the beach straight onto Llanddwyn Island, though at times of high tide it actually does become an island so a visit there shouldn't be undertaken without knowing the tide times.
On the island itself you'll find the ruins of St. Dwynwen's Church, a row of boat pilots' cottages - two which are restored and house a wildlife exhibition - an old lifeboat station and two lighthouses. The newer of these was built in 1845 and modelled on the Anglesey windmills, though it has been out of service for quite some time; the older lighthouse returned to service after a modern light was placed on top. The cliffs around the island support a wide variety of nesting seabirds, and a flock of Soay sheep and several wild ponies can be seen grazing near the chapel ruins.
With several lovely sandy coves and superb views of the Snowdonia hills, on a sunny summer's day Llanddwyn Island has a beautiful and somewhat magical quality, and the photo opportunities make it well worth the mile long walk from the car park to get there. You can see some photos of the beach and Llanddwyn Island in my post from June 5th 2014.