Weymouth Bay is a sheltered bay on the south coast of England in Dorset, and one of the locations for the sailing events of the 2012 Olympics. It is protected from erosion by Chesil Beach and the Isle of Portland, and includes several beaches, notably Weymouth Beach, a gently curving arc of golden sand which stretches from the resort of Weymouth, along to the suburbs of Greenhill, Lodmoor and Preston, and terminates just past Furzy Cliff at Bowleaze Cove a haven for watersports, windsurfing, scuba diving, jetskiing, surfing and swimming. This beauty has earned the bay the title of 'England's Bay of Naples'

The bay's waters are excellent for sailing the best sailing waters in northern Europe, one reason why it is home to the Weymouth and Portland National Sailing Academy which will host sailing events for the 2012 Olympic Games.

Weymouth Bay is situated approximately half-way along the UNESCO Jurassic Coast World Heritage Site, a 153-kilometre (95 mi) long stretch of coast, important for its varied geology and many unique landforms.

Chesil Beach, sometimes called Chesil Bank, in Dorset, southern England is one of three major shingle structures in Britain. Its toponym is derived from the Old English ceosel or cisel, meaning "gravel" or "shingle".

The beach is often identified as a tombolo, although research into the geomorphology of the area has revealed that it is in fact a barrier beach which has "rolled" landwards, joining the mainland with Portland Bill, giving the appearance of a tombolo. The shingle beach is 29 kilometres (18 mi) long, 200 metres (660 ft) wide and 15 metres (50 ft) high. The beach and the Fleet are part of the Jurassic Coast, a UNESCO World Heritage Site, and the location for a book, On Chesil Beach by Ian McEwan.

At the eastern end of the beach at the village of Chiswell, against the cliffs of the Isle of Portland, the beach curves round sharply to form Chesil Cove. This part of the beach protects the low-lying village from flooding. Westwards the shingle forms a straight line along the coast, enclosing the Fleet, a shallow tidal lagoon.

The beach provides shelter from the prevailing winds and waves for the town of Weymouth and the village of Chiswell, which would otherwise probably not exist

Varying with the Bank's unbroken increase in height, to 14.7 metres (48 ft), above mean high water, the size of the flint and chert shingle varies from pea-sized at the north-west end (by West Bay) to orange-sized at the south-east end (by Portland). It is said that smugglers who landed on the beach in the middle of the night could judge "exactly where they were" by the size of the shingle.

The area is the setting for On Chesil Beach, a novel by Ian McEwan.

From West Bay to Cliff End the beach is piled up against the cliff. At Cliff End a hollow forms behind the beach and at Abbotsbury a stretch of saline (or brackish) water called the Fleet Lagoon begins. The Fleet is home to many wading birds and Abbotsbury Swannery, and fossils can be found in the sand and mud.

Because of the low population density of nearby areas and their proximity to the naval base on Portland, the beach and the Fleet were used for machine gun training and bouncing bomb testing for Operation Chastise in World War II. Both Chesil Beach and the Fleet Lagoon are a Site of Special Scientific Interest, and the view of the beach from Abbotsbury has been voted by Country Life magazine as Britain's third best view.

The origin of Chesil Beach has been argued over for some time. Originally it was believed that beach material was from the Budleigh Salterton pebble beds to the west and later from Portland to the south east.