**On a private Gili Islands charter your cost per head is the flat boat fee divided by the number of people aboard — nothing else. A boat that fits ten costs the same whether four ride or ten do, so every extra head drops the per-person price. As of 2026, all charter fees are operator-set and subject to change.**
That single line of arithmetic is the whole story for a large group. This page is about the maths, not the seat-versus-charter debate: how to turn one flat quote into a real per-person number, how fast that number falls as your party grows, and what actually sets the boat fee you are dividing.
How do you work out per-head cost on a group boat charter?
Take one thing from the operator: the flat per-boat fee for your chosen boat, date-stamped “as of 2026.” Then divide it by the number of people who will actually be aboard. That quotient is your true cost per person. There is no per-seat surcharge on a private hire — you are buying the vessel, and the heads inside it split one bill.
Two numbers change the result: the fee and the head count. A bigger or faster boat raises the fee. A fuller boat lowers the per-head share. For a large group the second lever is the one you control, and it moves fast.
Worth stating plainly: there is no government tariff, marine-park price list, or regulation number that fixes Gili charter rates. The only publicly documented boat price in this stretch of water is the public slow boat from Bangsal, at roughly USD 1 per person — but that is a shared passenger ferry, not a private charter. Every charter figure below is a stand-in for an operator’s own quote, used only to show the shape of the maths.
What does per-person cost look like as the group grows?
Picture a boat that seats up to twelve at an illustrative flat fee of IDR 3,000,000 for the day. This number is invented purely to demonstrate the division — it is not a quote, not a published rate, and not an “official” price. Watch what the per-head column does as more people climb aboard.
| Heads aboard | Illustrative flat boat fee | Cost per person |
|---|---|---|
| 2 people | IDR 3,000,000 | IDR 1,500,000 |
| 4 people | IDR 3,000,000 | IDR 750,000 |
| 6 people | IDR 3,000,000 | IDR 500,000 |
| 8 people | IDR 3,000,000 | IDR 375,000 |
| 10 people | IDR 3,000,000 | IDR 300,000 |
| 12 people | IDR 3,000,000 | IDR 250,000 |
The per-head figure at twelve is one-sixth of what it is at two, off the exact same boat. That is the large-group advantage in one column: the fee is fixed, so filling seats is pure discount. When you are weighing this against buying individual seats, the fuller group charter vs shared boat comparison is where the money is decided — but the mechanism is always this simple division.
Two planning notes for big parties. First, confirm the boat’s real capacity before you divide — dividing by twelve only holds if the vessel legally and safely carries twelve. Second, ask whether the flat fee already includes fuel, guide, masks, and any island or conservation levies, or whether those ride on top and nudge your per-head number up.
At what group size does the per-head price beat a shared seat?
Divide the flat boat fee by your head count, then set it beside the operator’s per-person shared-seat price. The moment the division drops below that seat price, the private boat is cheaper — and it keeps improving with every extra head. For most operator pairings on the Gilis that crossover lands around four people. Below four, a shared seat usually wins; at four and up, a chartered boat’s per-head cost pulls ahead and never looks back.
For a group of eight, ten, or a full boat of twelve, the question is rarely “is it cheaper?” — the table already answers that. The real work is getting an accurate flat fee and an honest capacity, then splitting the bill cleanly.
What sets the flat boat fee you are dividing?
The numerator matters as much as the head count. Five things move the flat fee an operator quotes, all of them “as of 2026, subject to change”:
| Factor | Effect on the flat boat fee |
|---|---|
| Boat type | Glass-bottom sits lowest; small speedboat mid; small catamaran highest |
| Capacity | Larger hulls carry more heads but carry a higher flat fee |
| Duration | A full-day loop costs more than a half-day turtle-and-statue run |
| Fuel and route | Longer Trawangan–Meno–Air circuits burn more fuel into the fee |
| Season and demand | Peak dry-season weeks (June–July) firm prices up; shoulder weeks soften them |
Notice the tension for large groups: a bigger boat costs more in absolute terms but often less per head, because it fits more dividers. A twelve-seat catamaran at a higher flat fee can still beat a six-seat speedboat once you actually fill the bigger deck. Always compare the per-head result, not the sticker fee.
How do you split the cost fairly across a big party?
Once you have a per-head number, collecting it is its own small job. A few habits keep a large group from friction:
- Confirm the final head count before you divide. One drop-out on a per-boat charter raises everyone else’s share, unlike a shared tour where a no-show simply loses their own seat.
- Agree who covers extras. Drinks, GoPro hire, or a lunch upgrade should be pooled or paid individually, not smeared across the boat fee.
- Collect a deposit early. Operators typically hold the date on a part-payment; splitting that deposit up front avoids one person fronting the whole boat.
- Keep the quote dated. A fee gathered weeks out can shift by peak season; reconfirm close to the day so your division stays accurate.
The Gilis themselves add one logistical wrinkle a big group should plan for: the islands are vehicle-free. Wikipedia notes there is no motorised transport apart from electric scooters, and Audley Travel records that motorised traffic is banned by local order, so arrivals move on foot or by cidomo, the horse-drawn cart. A private boat can time its jetty drop-off around a large group’s walking pace instead of a mass disembarkation — a small comfort that costs nothing extra once the boat is already yours.
There is a forward-looking reason larger parties are increasingly booking whole boats early. As fast-boat crowds around the Gilis keep peaking and marine-conservation and mooring rules tighten heading into 2027, private day charters are drawing steadier demand from groups who want their own deck. Locking a big-capacity boat ahead of the busy dry-season weeks is getting less optional, not more — and the earlier you fix the flat fee, the sooner your per-head maths is settled.