How tides change Algarve beaches

Many first-time visitors arrive at a cove they saw in a photo and find only a strip of wet sand. Nothing is wrong: the photo was taken at low tide. In the Algarve, the tide decides what a beach looks like more than the weather does.

How big are the tides?

The Algarve has a semi-diurnal tide: two high tides and two low tides every day, about 6 hours and 12 minutes apart. Because the full cycle lasts slightly more than 12 hours, high tide comes about 50 minutes later each day.

How far the water rises depends on the moon:

In Lagos, for example, the average range is about 2.1 metres and the largest is close to 3.8 metres. Inside the Ria Formosa lagoon, the ebbing water can run through the inlets at more than 3 metres per second during spring tides, far faster than anyone can swim.

Beaches that shrink at high tide

The effect depends on the shape of the beach:

• Small coves under cliffs, such as many in Lagoa, around Lagos and on the west coast, can lose most of their sand at high tide. On beaches officially classed as limited use, the rising water pushes everyone into the zone where rock falls are a risk. See beach flags and cliff safety.
• Linked coves that you can walk between at low tide, through gaps in the rock or around a headland, are often cut off at high tide. People get stranded every summer.
• Long, open beaches such as Meia Praia, Armação de Pêra, Falésia and Monte Gordo keep plenty of sand at any tide.
• Island beaches in the Ria Formosa stay wide on the ocean side, but the lagoon side changes dramatically, and ferry and water-taxi routes can be affected at very low tide.

On our beach guides we note what each beach looks like as the tide rises and show it in our photos.

Caves and arches

Several caves and arches can only be seen at lower tides, and some are accessible by boat or kayak only. At the Benagil caves, swimming in from the beach is banned under rules in force since 13 August 2024, and boats and guided kayaks are not allowed in when visibility is under 1,000 metres. Tides and swell also decide whether tours can enter at all, so a tour may be moved or cancelled even on a sunny day.

How to read a tide table

The official tide tables come from the Instituto Hidrográfico, the Portuguese navy’s hydrographic office, with stations at Lagos, Portimão and Faro. Lifeguard posts, surf schools and harbours often display the day’s times too.

A tide table lists the time and height of each high tide (preia-mar) and low tide (baixa-mar). Look for:

1. The time of low tide. Plan to be on a small beach from about two hours before to two hours after it.
2. The height. A low tide of 0.5 metres uncovers far more sand than a low tide of 1.5 metres.
3. The moon. Around full and new moon, low tides are lower and high tides are higher than usual.

Waves and swell matter as much as the tide. A moderate high tide with a big swell can still sweep up to the cliffs. Check the wave forecast from IPMA, the national weather institute, before walking around a headland.

How the coastline keeps changing

The Algarve coast is not fixed. Tides, waves and storms move enormous amounts of sand every year, and the shape of the coast changes from one season to the next.

Cliff retreat. The limestone and sandstone cliffs between Sagres and Vilamoura erode constantly. Waves undercut the base and blocks fall, which is why new caves, arches and sea stacks form, and old ones collapse.

The moving inlets of the Ria Formosa. The barrier islands east of Faro are separated by inlets that migrate along the coast. The Ancão inlet, at the western end of the lagoon, was artificially moved westwards in 1997. Between 2007 and 2011 it travelled about 1 kilometre to the east again, helped by storms that overtopped and breached the barrier in the winter of 2009 to 2010.

Storms and sand nourishment. After a run of storms between October 2025 and early March 2026, Portugal’s environment agency recorded damage on 35 Algarve beaches. At Praia do Peneco in Albufeira, the beach retreated by up to 24 metres. In spring 2026, work began to put about 1.3 million cubic metres of sand back onto the most eroded beaches, mainly along the 6.6 km stretch from Quarteira to Garrão, in a project budgeted at €14.3 million. Sand nourishment like this has become a regular part of keeping Algarve beaches usable.

For visitors, the lesson is simple: a beach can look very different from one year to the next. That is why our beach guides show the date of our last visit.