Just five miles from Cardiff and Barry, the Island of Flat Holm or Ynys Echni Marconi transmitted the first wireless signals over open sea from Flat Holm to Laverlock. Because of dangers in the Bristol channel and frequent shipwrecks a lighthouse was built on the island, which was replaced by a Trinity House lighthouse in 1737 the tower was re engineered in 1820 and 1866.
Steep Holm is a privately owned island also in the Bristol Channel and is managed by a small group of Trustees. It lies about five miles offshore from the seaside resort of Weston-super-Mare in Somerset. Although relatively close to areas of high population, and sitting in the middle of a busy shipping channel.
Sully Island is a small tidal island and Site of Special Scientific Interest at the hamlet of Swanbridge, Vale of Glamorgan, The RNLI run at traffic light system to give the public safe crossing times.