We run the Algar de Benagil every summer day from Portimão, in every kind of light and most kinds of sea. “When should I come?” is the third question we field most often — right after “how do I get there?” and “can I still swim in?”. This piece is the deep answer: which month, which hour, which tide. The full picture on the cave itself lives in our complete Benagil Cave Tour guide.
The Short Answer
The best time to visit the Benagil cave is late May, June, or September, between 10:00 and 13:00, when the skylight beam falls directly into the cave and the cave is least crowded. For the emptiest cave, take the first boat between 07:30 and 09:00 — softer light, no other boats inside.
May through October is the running window. July and August have the strongest beam but routinely three or four boats inside at midday. November to March, operators run on calm days only — Atlantic swell over 1.5 metres closes the cave. Tide matters less than the generic blogs say.
Month by Month
Every month at the cave reads differently. May, June, and September are the sweet spot; July and August are peak; November to March, we run when the Atlantic lets us — roughly one day in five.
| Month | Crowds | Water | Cave clearance |
|---|---|---|---|
| April | Very light | 16–18 °C | ~85% |
| May | Light, climbs mid-month | 18–20 °C | ~95% |
| June | Moderate | 20–22 °C | ~98% |
| July | Heavy | 22–24 °C | ~99% |
| August | Peak | 23–25 °C | ~99% |
| September | Moderate, thins after week 1 | 22–24 °C | ~95% |
| Oct (1st half) | Light | 20–22 °C | ~85% |
| Nov–Mar | Empty when running | 15–17 °C | 20–40% |
April
Soft, side-lit light without the full beam — the sun is too low until the last week. The cave runs most calm mornings, but about one in seven cancels for swell. Water at 16 to 18 °C is too cold for a long swim stop. If the empty cave matters more than the photo, April is the pick.
May
The transition. First half feels like April with warmer afternoons. From mid-May the beam appears, water climbs into the high teens, and schedules fill out. By the last week the late-morning shaft is sharp enough for the photograph everybody comes for, with the cave still pre-summer. Late May is the operator favourite.
June
Full summer without August’s volume. Days run long (sunset after 21:00), beam strongest from 10:30 to 12:30, and we cancel maybe three mornings a month for swell. The cave at midday holds two or three other boats; the 07:30 boat almost always has it to itself. The month we would send our own family on.
July
Peak. Water 22 to 24 °C, beam at its strongest, every operator on full schedule. From 10:00 onward the cave routinely has three or four boats inside, and midday photos include other tours in frame. Book three to five days ahead. Our counter-recommendation: take the 07:30 boat.
August
Hottest, busiest, most expensive. Water at 23 to 25 °C, the Atlantic flat almost every day, the cave at midday holding four or more boats. Cancellations practically zero. If August is your only window: first departure, weekdays not weekends, accept the famous beam photo will share the frame.
September
Quietly the #1 month. Water still at its annual warmest in the first half, crowds thin sharply after week one, beam strong with slightly warmer light than July or August. The September photo most travel blogs publish under an August caption is the better one: softer light, half the boats.
October to March
October’s first two weeks are essentially summer — beam softening, ~85% running. After about 20 October the wind picks up. November to March, we only run on calm windows; cancellation odds 60 to 80%. The cave does not “close” — it becomes unenterable on swell over 1.5 metres, and that swell is the rule, not the exception. On the rare calm winter days that do run, the cave is empty in a way no summer morning matches.
When the Skylight Beam Falls
The skylight beam falls into the Benagil cave roughly between 10:00 and 13:00 from May through October, when the sun is high enough to shine through the opening. The window shifts slightly later in winter, earlier in midsummer. For the strongest beam, aim for late morning; for softer light, take the first boat.
In June and July the window stretches to 09:30–13:30; in October and April it tightens to 10:30–12:30 and lands at a lower angle, falling on the cave’s west wall as much as the floor. Fully overhead, the beam paints a column of direct light on the sandy beach and fills the cave with diffused bounce off the walls — without that bounce, the beam alone would read as a spotlight.
First Boat vs. Midday Beam
Most photographers who actually know the cave prefer the 07:30 first boat to the 10:00–13:00 beam window. The first-boat light is softer and diffused, the cave is empty (one other boat at most), and the photos compose without other tours in frame. The midday beam is striking but crowded.
The first boat gives you the cave to itself for about five minutes; by 10:00 in July that is gone. The case for the midday beam is one specific photograph — the one everybody pictures when they think of Benagil. If that exact frame is what you came for, take the midday boat and accept the two to four other tours sharing the cave. Otherwise the first boat wins.
Does the Tide Matter?
Tide matters less than the generic blogs say, and sea state matters more. The Algarve’s tidal swing is under three metres; at low tide the cave’s interior beach is wider and the arch about 40 cm taller, but the cave is enterable across the full tidal range when the sea is calm. Atlantic swell over 1.5 metres closes the cave regardless of tide.
Above 1.5 metres of swell, most reputable operators stop entering; some draw the line lower (1.2 m), almost none higher. Direction matters too — southwesterly swells stack the entry, northwesterly slips past. We check the swell forecast every morning before we run; the tide chart only comes out on an already-running day.
When the Cave Shuts: Cancellation Reality by Season
Cancellations are normal in shoulder season and routine off-season. Peak summer (July, August): under 2% of days cancel. Shoulder (May, June, September, early October): 5 to 15%. Mid-October to March: 60 to 80%, depending on the Atlantic. The cave does not “close” — operators just do not run when the swell makes entry unsafe.
We cancel about three days a month in June. By November it is twenty. By February it is most of the month. Book direct for faster weather updates, avoid the first and last day of your trip, and have a Plan B for off-season — the clifftop viewpoint works on a windless winter day.
Which Window Should You Pick?
If your dates are flexible, aim for late May, June, or September. If you are locked into July or August, take the first boat (07:30 to 09:00); same cave, half the crowd. Off-season, book a flexible operator and have a backup plan. For the skylight beam, plan around 10:00 to 13:00.
By reader type: photographer — first boat year-round, late May or September if flexible. First-timer — June or early September on a midday boat. Off-season visitor — the cave is a bonus on a trip already worth taking for the empty coast. Our Benagil cave speedboat tour leaves from Porto Comercial de Portimão (signposted Ac. Porto Comercial de Portimão) and runs first departures from 07:30 between May and October.
Ready to Pick a Date?
For the full picture on the cave itself — boats, ports, rules, what to pack — our full Benagil Cave Tour guide is the next read. For the broader month-by-month view across all Algarve boat tours, the lens widens beyond the cave. Questions about a specific week or tide? Message us — we will tell you straight what your dates are likely to look like.
