Outer Islands

For most divers, the best all-round windows are April-May and October-November. Those transition months usually bring calmer seas, easier boat logistics, and stronger visibility around Alphonse and Desroches, with water commonly sitting near 27°C to 29°C. If Astove or Cosmoledo is the main goal, many operator schedules also concentrate from November into April, when the far-south logistics are more workable. June-September is not impossible, but stronger southeast trades can make exposed walls, crossings, and advanced sites far less comfortable, especially if you are newly certified or traveling with mixed abilities.

Aim first for April-May or October-November. Those are the months when the sea surface is usually friendliest for snorkeling, freedive instruction, and mixed-ability boat sessions around Alphonse, Desroches, and selected southern atolls. Calm water matters more here than raw temperature because blue-water wildlife trips, channel drifts, and freedive coaching all become harder once the southeast trades build. December-March can still be warm and rewarding, but humidity and rain increase. June-September is the period to be cautious with expectations, using sheltered reef or lagoon sessions more strategically rather than assuming every outer-reef plan will run smoothly.

Almost everyone enters through Seychelles International Airport on Mahe, then continues by resort-arranged or operator-arranged small aircraft. Desroches is the easiest onward island, with an official 35-minute scenic flight booked through Four Seasons. Alphonse is about one hour from Mahe and is best treated as a managed transfer rather than a normal domestic hop. Astove is more specialist and seasonal, while Cosmoledo is usually reached as part of a combined itinerary that includes Astove plus a boat crossing. In practice, you should think of Mahe as the logistics hinge and leave a buffer night there if your international connection is tight.

You need a pre-departure Electronic Travel Authorisation even though Seychelles is broadly visa-free for most visitors. The eTA is completed before you fly, and on arrival immigration still expects the usual supporting basics: a valid passport, onward or return travel, confirmed accommodation, and proof of funds. The initial visitor's permit is currently free for up to three months if you meet entry requirements. Outer-island travelers should keep all confirmations saved offline because your next flight after Mahe may be operator-managed and internet access later can be patchy. Also check yellow-fever documentation rules if your routing includes a risk country.

You do not need to be a technical diver, but you should be a genuinely comfortable recreational diver with recent experience, solid buoyancy, and calm responses in current and blue water. Astove's Wall is a serious remote-ocean dive, not a check-the-box holiday drift. Divers who are newly certified, rusty, or uneasy around fast depth changes will usually enjoy Alphonse or Desroches more. A good benchmark is Advanced Open Water level with recent logged dives in current and from boats. Bring your own SMB, computer, and save-a-dive basics, and expect conservative briefings because evacuation margins are very different from mainland dive destinations.

Yes, especially on Desroches and Alphonse. Desroches works best for non-divers because the whole island can be explored by bicycle and includes beaches, the tortoise sanctuary, the Discovery Centre, birding, spa time, and guided snorkeling. Alphonse is excellent for wildlife-minded travelers who like turtle patrols, St Francois nature hikes, farm visits, and quiet beach time. Even Astove can be memorable for the right person, but only if they enjoy isolation and expedition atmosphere rather than classic resort entertainment. The mistake is choosing the farthest island for someone who mainly wants restaurants, shopping, or nightlife, because those are not the point here.

Realistic targets include turtles year-round, reef fish in huge numbers, rays, barracuda, tuna, trevallies, and healthy coral structure on almost every good day in the water. Around Alphonse and St Francois, reef manta action is especially worth prioritizing in October-December. Astove is a strong turtle and pelagic destination, while Cosmoledo adds sharks, giant groupers, and very wild-feeling reef scenes. Around Desroches, turtles are a major draw both in the water and on nesting beaches, especially October-March. Humpback whales can pass through July-October, but treat whale sightings as a bonus rather than the reason to book.

The government layers are straightforward: the eTA currently starts at EUR 10.90 for standard processing, the initial visitor's permit is free if you meet entry conditions, and island-resort stays now carry a Tourism Environmental Sustainability Levy of SCR 100 per person per night. The real budget pressure comes from outer-island trip design itself, because flights, specialist activities, and remote logistics push the overall experience into premium territory. Cash needs are low once you reach the islands, but it is smart to carry some SCR on Mahe for taxis or small purchases. Always read the operator invoice for activity supplements or conservation contributions.

Start with insurance. You want comprehensive travel insurance with remote medical evacuation, and divers should add dive-specific cover. Then pack as if replacement options are poor, because once you leave Mahe they usually are. Carry all prescription medication, charging essentials, save-a-dive spares, seasickness medication, and sun protection in hand luggage. Be honest about your current fitness, recent diving, and comfort in chop. Desroches has the strongest documented on-island clinic, but serious cases across the region may still require evacuation to Mahe. The best mindset is conservative, hydrated, and willing to let weather or guides change the plan.

Pack lighter and smarter than you would for a large-resort trip. Use a soft duffel, keep regulators, camera gear, batteries, medication, and documents in carry-on, and assume baggage space on onward flights is tighter than on your long-haul. For scuba, a 3mm suit, booties, SMB, computer, and basic save-a-dive kit are the essentials. For snorkeling and freediving, bring the mask you trust, a rash guard, dry bag, and anti-fog. Topside, the big items are a sun hat, light long sleeves, sandals that handle hot sand, and a power bank. Remote islands punish overpacking and reward redundancy in the right small things.