Walraversijde is an abandoned medieval fishing village on the Belgian coast, near Ostend. It was rediscovered in 1992 in a dune area, near a medieval dyke. Archeological research showed that it had been occupied, in two phases, between 1200 and 1600. Walraversijde has been studied more thoroughly and more systematically than any other medieval fishing community in Europe. The village has been partially reconstructed and has a museum, Walraversijde Museum, dedicated to the site.

Walraversijde was discovered in 1992 on the Belgian coast by the archeologist Marnix Pieters. It was found in a dune area near a medieval dyke. Prior to discovery, Walraversijde was a lost village, with no obvious remains above ground. Two related sites were excavated, one on a beach and the other on a polder. The beach site was inhabited between 1200 and 1400, and the polder site was inhabited between 1400 and 1600. The excavations also found evidence of activities during the Roman era, such as a Roman dyke.

Walraversijde ceased having a role after the Siege of Ostend of 1601–1604 when a Spanish cavalry camp operated from the site. The artefacts and remains are well preserved, and there have been many finds. The sites have been excavated systematically and thoroughly, and have produced unusually rich findings.

The village of the earlier beach phase of Walraversijde was located behind a protective dune belt. The houses were arranged in small, loose groups, the largest house measuring 7 by 12 metres (23 by 39 ft). Written sources indicate the villagers fished, traded salted fish and other goods, and sometimes engaged in piracy. They probably also dug peat to produce salt. However, the dune belt was maintained badly and Walraversijde became vulnerable. In 1394, a flood drowned the town of Ostend and caused heavy sand drifts and floods around the village. Walraversijde ended up in front of the dunes and had to be rebuilt further inland.

The new Walraversijde was relocated on a polder protected by a new dyke. At least 100 houses were built, with widths between 3.7 and 8.8 metres (12 and 29 ft) and lengths between 12.4 and 17.5 metres (41 and 57 ft). They were built mainly using brick, often plastered inside and outside. Some houses had stained windows. Floors were brick or sand-covered clay, and roofs were thatched with reeds, straw, or galingale.

There were also community spaces, such as a draeyplaetsen for making cordage, a brewery, and a caetsspel (gaming house and brothel). Around 1435 a chapel was built. As might be expected for a settlement preoccupied with the sea, the occupation density was much higher than in non-fishing rural communities. No spaces were set aside for stables, gardens, or fields between houses.

Between 1383 and 1413, under the supervision of the admirals of the Count of Flanders and the Duke of Burgundy, privateering and piracy took place between English and Flemish fishing and trading vessels. The fishermen of Walraversijde participated in this privateering to the degree that they were warned not to plunder or damage ships at sea unless ordered to do so by the duke. In addition to acting as privateers under the orders of the duke, Walraversijde fishermen supplied the duke's fleet with vessels and the fishing fleet with guard boats throughout the fifteenth century.

The villagers had commodities one might not expect to find in a medieval fishing community. There were "exotic spices such as paradise grains, cloves, and pepper, exotic fruits such as pomegranates, ivory combs, cast bronze candlesticks, and luxury ceramics." The piracy, privateering and also beachcombing must have played a part in this, as probably also did the piloting of Spanish merchant vessels by Walraversijde fisherman to the port of Bruges.