Ask anyone who lives here when the sea is best and you will get the same answer, usually with a slightly smug expression: now. The water off Ibiza has spent all summer absorbing heat, and by the second week of September it is at its warmest of the entire year — somewhere around 26°C, warmer than the air on a cloudy morning. Meanwhile the August fleet has gone home, the wind drops into those long glassy mornings, and boat trips that were fully booked three weeks ago suddenly have space on the 10:30 departure.
If you are on the island this month and you are only looking at it from a sunbed, you are missing the better half. Ibiza was built facing the water. The cliffs on the west coast, the sea caves under Punta Galera, the reserve islands off San Antonio, the whole silhouette of Es Vedrà — none of it makes sense from the road. Here is how to get out there, from a five-euro commuter boat to a four-hour sunset run, with what things actually cost this September.
Why September is the month to get on the water
Three things line up. The sea temperature peaks now, which means you can swim off the back of a boat for an hour without the shiver you get in June. The Mediterranean is at its calmest between the August meltemi and the first autumn fronts, so crossings that can be choppy in high summer tend to be flat. And demand has dropped: operators that ran three full departures a day in August are running two, with room on both.
There is a practical bonus too. Light in September is lower and warmer by late afternoon, which is why the sunset departures — the ones leaving San Antonio around 16:30 — are worth more now than they were in July. The sun sets earlier, so you are back on land at a civilised hour rather than at midnight.
The cheap crossings locals actually use
Not every trip on the water needs to be an excursion. Ibiza has a small network of working boats that function as buses, and they are absurdly good value.
The Aquabus Beach City Boat runs between Ibiza Town and Playa d'en Bossa from around 09:45, and costs between €5 and €15 depending on whether you go single or return. It takes about fifteen minutes, saves you the parking nightmare at Bossa, and gives you the approach to Dalt Vila from the sea, which is the way the town was designed to be seen.
From San Antonio, the Cala Salada ferry boat costs €7 to €12 and drops you at one of the island's best coves — the one where the road down is narrow, the car park fills by ten and the walk back up in the heat is nobody's idea of a holiday. Taking the boat solves all of that. Departures start around 11:00.
On the east side, the shuttle ferry between Ibiza Town, Santa Eulària and Es Canar runs from €9 to €34 depending on how far you go. It is a genuinely pleasant way to move along the coast, and in September the deck is not a scrum.
Formentera in a day: which crossing to book
Formentera is the reason most people get on a boat here, and there are more ways to do it than most visitors realise.
The fastest is the Balearia crossing from Ibiza port, 30 minutes, departures roughly every half hour with the first at 07:00 and the last return from Formentera at 08:00 the following morning cycle. Fares run €27.50 to €55 return, with 20 kg of luggage included per passenger. If you want the most time on the island for the least faff, this is it — and going out on the 07:00 in September means you are on Ses Illetes before the day-trippers.
If you are staying on the east coast, the Santa Eulària ferry to Formentera (€24–€52) saves you the drive into town. From the south, the Figueretes and Playa d'en Bossa crossing runs €22 to €45. And from San Antonio, Cruceros Portmany goes for €22 to €44, though the crossing is longer from that side of the island.
Prefer not to plan anything? The Formentera Tour run by Excursiones Al Sabini (€45–€100) includes hotel pickup, the ferry and a guided bus loop taking in La Savina port, Sant Francesc Xavier, the clifftop viewpoint and lighthouse at La Mola, Es Pujols and the salt flats. You can also take the same package and just be dropped at a beach for the day.
The west coast classics
Two trips out of San Antonio have earned their reputation, and both are on the cheaper end.
The Natural Park Aquarium Boat Trip with Capitan Nemo (€20–€39, three mornings a week, departing 11:00) is the quiet gem. Three hours along the northwest coast, calling at Cap Blanc Aquarium — an old lobster nursery carved directly into a sea cave, now home to endemic species of these Pityusic waters. The route passes Cala Gració, Cala Gracioneta, Cala Salada, Cala Saladeta and Punta Galera before reaching the Margaritas Islands. For under forty euros it is the best value coastal tour on the island.
The San Antonio to Es Vedrà sunset trip (€23–€45, four hours, departing 16:30) is the other one. You track south past Cala Bassa, Cala Conta, Cala Molí, Cala Vadella, Cala Carbó and Cala d'Hort, then circle Es Vedrà itself while the crew unpacks the mythology that has attached itself to that limestone monolith over the centuries. There is a swim stop at Cala Bassa or Cala Conta, conditions permitting. Going in September means the sun sets during the return leg rather than after it.
When you want the water to yourself
If the appeal is the swimming rather than the sightseeing, look at the smaller operators. The Cave and Beach Hopping Boat Tour with TAKE OFF (€70–€100, three hours from 10:30) carries snorkel and paddle-surf gear and works the sea caves cut into the western limestone, including a stop at a protected reserve island. SUP Paradise runs a three-hour trip with a paddle surf lesson and snorkelling built in for €75. And TAKE OFF's Luxury Water Toys Experience (€110–€160) caps groups at twelve and brings Seabobs, a Schiller water bike and a floating platform, working the coves north and south of San Antonio.
For something entirely different, Cova de Can Marça above Port de Sant Miquel (€9–€15) is a 40-minute guided walk through a limestone cave system that smugglers used for decades. It is the coastline seen from the inside, and a good call on the one September afternoon when the wind gets up.
Practical notes before you book
Book the day before rather than the morning of — September has space, but the good departures still fill. Check the forecast for wind rather than rain: a north-easterly will cancel west-coast trips even under a blue sky. Bring a light layer for the return leg, because the temperature drops noticeably after six. Reef-safe sun cream matters more than you think on a boat, where there is no shade and the water reflects everything straight back up at you. And if you are prone to seasickness, take the morning departure — the sea is almost always flatter before noon.
The season on land is winding down. The season on the water has about six good weeks left, and these are the best of them.
Find every boat trip, ferry crossing and sunset departure running this week on the ibiza-calendar.com agenda.
