How many other people will be on your boat

The smallest boat we track has four cabins. The largest has fifty-six. Both will sell you a night on the same water, in the same weather, stopping at the same caves, and the median price of the small end of the fleet is $27 below the median price of the big end.

Fourteen times the size for roughly the same money. That is the strangest number in our whole data set, and almost nobody chooses on it.

What the fleet looks like

Cabins	Boats	Median rate, 2 days 1 night
9 or fewer	3	$128
10 to 19	20	$142
20 to 29	26	$141
30 or more	21	$155

The median across all seventy is twenty-two cabins. Cabin count is not passenger count, and no operator in our set publishes the second figure, so double it for a rough guess and treat the result as rough. A fifty-six cabin boat is carrying something near a hundred people. A ten cabin boat is carrying twenty.

The price column is the point. Between the smallest band and the largest the median moves $27, on a product where the cheapest boat in the fleet is $80 and the dearest is $615. Whatever you are paying for in Ha Long Bay, it is not the number of strangers at breakfast.

The number that looks backwards

We classified 7,104 written reviews by subject. One of the subjects is whether the guest remarked on how many people were around them, favourably or not.

Boat size	Reviews	Mentioned the headcount	Share of those in a negative review
14 cabins or fewer	1,253	9.3%	6%
15 to 24	3,404	7.1%	13%
25 to 34	950	5.3%	14%
35 or more	1,497	4.2%	17.5%

Read only the third column and you would conclude that small boats feel more crowded, because their guests bring the subject up twice as often. That reading is wrong, and it is the sort of wrong that ends up printed.

The fourth column shows what is happening. On the smallest boats, 6% of the people who mention the headcount are writing a negative review. On the largest, 17.5% are. Guests on small boats raise the subject because they liked it. One writes that the ship is quiet since there are only ten rooms. Guests on large boats raise it because it got in the way.

The same flip shows in the bad reviews alone. Among one and two star reviews, headcount comes up in 6.1% on the smallest boats and 12.9% on boats of fifteen to twenty-four cabins. Twice as often, from the people who were already unhappy.

What else changes with size

Two other subjects move steadily as boats get bigger, and both point the same way.

The crew get mentioned in 89% of reviews of boats with fourteen cabins or fewer, and 71% of reviews of boats with twenty-five to thirty-four. On a small boat the crew are individuals with names. On a large one they are staff.

Kayaking gets mentioned in 12.3% of small-boat reviews and 5.2% of the largest. We cannot tell you whether that is because big boats run fewer sessions or because a kayak launch for a hundred people is less memorable than one for twenty. The gap is real either way.

The rate of one and two star reviews is lowest on the smallest boats, at 3.9% against 5.1% to 5.7% elsewhere. It is a modest difference and we would not build a decision on it alone.

The catch

A small boat concentrates you. Twenty people, one deck, one dining room, two nights. If the group is wrong, or one couple is loud, there is nowhere to go and no other table to sit at. On a forty-cabin boat you can disappear, and some people book precisely for that.

Small boats also carry less public evidence. Our smallest band rests on eight boats and 1,253 reviews, against twenty-one boats and 3,404 for the middle. Twenty of the seventy boats we track have no collected reviews at all, and several of those are small. A quiet record is not a good record.

And the amenities thin out. A boat with four cabins is not carrying a pool, a spa and three bars. If your idea of the trip includes wandering off to a sundeck that is not the same sundeck you had lunch on, you want the big end of the fleet, and you should not read the numbers above as an argument against it.

One more limitation worth stating plainly. We have not counted anybody. These figures come from cabin counts the operators publish and from what guests chose to write, not from a headcount at dinner. A boat can sail half empty in a slow week and the cabin count will not tell you.

Common questions

So what size should I book? If you want the crew to know your name and the anchorage to be quiet, book under fifteen cabins and accept a shorter amenity list. If you want space to escape into and a full deck of facilities, book over thirty and expect to queue at the tender. The money will be about the same, which is what makes this a genuine choice rather than a budget decision.

Are small boats more expensive? No, and that surprises people. The median for boats of nine cabins or fewer is $128 against $155 for boats of thirty or more. The very cheapest and the very dearest boats in our set are both at the small end, so the band tells you less than the individual boat does.

Does a small boat mean a private one? No. Private charter is a separate product and a different price. A four cabin boat still sells cabins to strangers.

How does this interact with which bay I pick? It mostly does not, which is useful. Bai Tu Long has the fewest boats on the water, so it is the quiet option regardless of the size of the boat you are standing on. Our bay comparison has the counts.