I have been on perhaps thirty boat trips of the kind sold from kiosks along a seafront. Most were fine, four were genuinely excellent, and three were bad enough to be worth learning from.
The differences were visible before boarding in every case.
The boat itself tells you a lot
Not whether it is new, which correlates with price rather than with quality.
What to look at: whether there is shade, and how much. A four hour trip in open sun with no cover is genuinely unpleasant and this is the most common complaint I hear.
Seating, and whether there is enough for the number of tickets they are selling. Standing for four hours on a moving deck is different from standing for four hours.
Whether there is a toilet, which for anything over about two hours is not a luxury.
And how the safety equipment looks — whether lifejackets are visible, accessible, in a range of sizes including children's, and not obviously perished. An operator careless about this is careless about other things.
Ask how many people are booked
The single most useful question and almost nobody asks it.
A boat that holds forty and has twelve booked is a different experience from the same boat with forty. Room to move, room to sit in shade, a crew that has time to talk to you.
Operators will usually answer honestly, and if they will not, that is informative in itself.
This is also the argument for going early or late in the season, and for the first trip of the day rather than the middle one.
The itinerary claims are frequently optimistic
Where the disappointment usually comes from.
Trips are advertised with a list of stops and a duration. What is rarely stated is how long is spent at each, how much is transit, and what happens if conditions do not allow a stop.
A four hour trip visiting five places is spending very little time at any of them, and a substantial part of that four hours is travelling.
Ask specifically how long you get at the main thing you are going for. The answer is often twenty minutes when people are imagining an afternoon.
Also ask what happens if the sea is too rough for a particular stop, which is common and which good operators will tell you about honestly.
Wildlife trips need particular care
The category where expectations and reality diverge most.
Any operator guaranteeing sightings of wild animals is either lucky, misleading, or doing something to the animals that they should not.
The honest ones give a success rate, which is generally high in the right season and never a hundred percent, and many offer a repeat trip if you see nothing.
What to look for is whether they follow guidelines about approach distance and time spent with animals. Operators that chase, surround or feed are causing genuine harm, and it is quite visible from the boat once you know to look.
Trips run by or in partnership with research organisations tend to be both better behaved and more informative, and they are usually not the ones with the biggest signs on the seafront.
Seasickness, honestly
Underdiscussed by operators for obvious reasons.
Conditions vary enormously and a calm harbour tells you nothing about what is happening beyond the headland. Ask the crew directly what the swell is like outside, and take the answer seriously.
If you are susceptible, the standard measures do work — medication taken well in advance rather than when you start feeling ill, sitting low and central, looking at the horizon, staying outside rather than in a cabin.
And a smaller boat moves more than a larger one, which is worth weighing against the smaller boat's other advantages.
The signs of an operator worth choosing
The crew know the area rather than reciting. Ask a question about something you can see and note whether the answer is specific.
They cancel when conditions are poor. Ask whether they have cancelled recently — an operator that never cancels is an operator that goes out in conditions they should not.
They carry fewer people than the boat's maximum.
They are locally owned rather than a booking agent selling somebody else's trip, which you can usually determine by asking who actually runs the boat.
And they are booked up, which is the crudest signal and is not useless.
The three bad ones
For completeness. One was overloaded and I stood for three hours. One spent most of the advertised duration motoring between places with almost no time at any of them. And one pursued a group of animals aggressively enough that several passengers complained.
All three were bookable from a kiosk with photographs, sold by somebody who had never been on the boat, at a price slightly below the alternatives.
Paying and cancelling
Two practical points. Booking directly with the operator rather than through a seafront agent usually costs less and means you are dealing with the people who run the boat when something changes.
And ask the cancellation policy for weather specifically. Good operators reschedule or refund without argument when they cancel. Some agents do not refund at all, which is worth knowing before rather than after.
The same applies to your own cancellation. Trips are frequently non-refundable within a day, which matters if you are booking several days ahead on an uncertain forecast.