Praia da Costa de Santo André

North of Sines, the Alentejo coast becomes one long, straight run of sand. Costa de Santo André is a small settlement on that stretch, in the municipality of Santiago do Cacém, and its beach is a wide open strand facing the Atlantic. What makes it different is what lies behind the dunes: the Lagoa de Santo André, a large coastal lagoon that is part of a nature reserve.

For a family, that gives you two outings in one place. The sea beach, with lifeguards and a Blue Flag, is for swimming and sandcastles. The lagoon side is for birds, walks and a lesson in how coasts work.

The Portuguese state created the Reserva Natural das Lagoas de Santo André e da Sancha in 2000. The Santiago do Cacém tourism office explains that the lagoon is an important stop for migrating birds, where many species rest, pass through and nest, and that the reserve has a bird observation and ringing centre. The reserve was set up to protect these two wetlands, the dunes around them and the strip of sea next to them. The council’s list of plants recorded in the reserve runs to 510 species.

Children who like big natural events will enjoy the story of the lagoon’s opening. Each year the lagoon is usually opened to the sea in March: machines cut a channel through the sand so that sea water can renew the lagoon and fish can move in and out. In February 2026, after weeks of storms, the lagoon broke through to the sea on its own, which the local parish president described as rare. The parish president added that the lagoon has to stay open for a while to clean and renew its water, or machines may still be needed.

Costa de Santo André had a Blue Flag in 2026, with a bathing season from 13 June to 15 September. It is also on the 2026 national accessible-beach list, although that list shows no special bathing equipment or staffed assistance service here, so ask locally what access is in place before you rely on it. APA data shows the bathing water was rated Excellent in 2025.

The council gives the average sea temperature during the bathing season as between 16°C and 19°C. That is fresh, especially for small children, so a wetsuit top or a quick in-and-out is sensible. This is open Atlantic coast, so check the lifeguards’ flag and swim in the area they are watching. Outside the season there are no lifeguards.

The settlement has an unusual history. According to the council, fishermen and their families from Ílhavo, near Aveiro, arrived at Costa de Santo André around 1855. They built huts and stores of thatch and reed, fished for sardine at sea in summer and for other fish in the lagoon in winter, and used the arte xávega, a method of hauling nets onto the beach by hand with high-prowed boats. An 1863 census recorded just six households and 18 people.

Their saint’s day tradition carries on. The big local festival is São Romão, on 9 August, when people from the surrounding villages used to arrive at dusk the evening before and spend the night and the next day on the sand.

The council’s pages focus on the reserve and history rather than beach services, so we can’t list toilets or cafés with confidence. Expect a settlement with seasonal beach life in summer, and bring water, snacks, sun cream and your own shade, since there are no trees on the sand.

The council says Costa de Santo André and the neighbouring Fonte do Cortiço get very busy in July and August. The sea is cool and exposed, with no breakwater or headland to calm it. And the lagoon is a nature reserve rather than a designated bathing beach, so enjoy it from the paths and viewpoints and keep dogs and children away from nesting areas.

Just south, Fonte do Cortiço, also known as Areias Brancas, lies entirely inside the reserve with a long beach of very pale, fine sand, dunes and pine woods behind; it also had a Blue Flag in 2026. Inland, Badoca Safari Park is close to Vila Nova de Santo André, and the municipal pools in Santiago do Cacém are a backup on a windy day. The sheltered town beach at Sines is the calmest sea water nearby for toddlers.

Is Costa de Santo André beach good for children?

It has lifeguards in season, a Blue Flag and plenty of room. It is open Atlantic coast with cool water, so keep small children close at the edge.

When are there lifeguards at Costa de Santo André?

In 2026, from 13 June to 15 September.

Can you swim in the Lagoa de Santo André?

The lifeguarded bathing area is the sea beach. The lagoon is part of a nature reserve; treat it as a place for walks and birdwatching.

How warm is the sea at Costa de Santo André?

The council gives average summer sea temperatures of 16°C to 19°C.

What is the opening of the lagoon?

Most years, usually in March, machines cut a channel so the lagoon can drain into the sea and renew its water. In February 2026 it opened naturally after heavy storms.