The fastest boats in GTA Online are often not what players expect, as the true top speed differs from what is shown in-game.
A boat's top speed doesn't really compare favorably to the top speed of other vehicle types (planes, helicopters, cars), but they are still a viable way of traveling through bodies of water in GTA Online. It is vital to note that only boats will be ranked on this list. No submarines, planes, etc., will be listed.
Another important thing to note is that most boats tend to be displayed as faster than they truly are in GTA Online. As a result, this list showcases their true speed as calculated by Broughy, as that's the best method for determining top speed objectively. However, some exceptions, such as the #1 entry, go faster than what the game displays.
Top five fastest boats in GTA Online based on top speed
#5 - Seashark
The Seashark clocks in at 67 mph (107.83 km/h), making it the fifth-fastest boat in GTA Online. Considering it only costs a measly $16,899, that's actually quite the impressive feat.
Sure, the top speed is low compared to other vehicle variants, but its cheap price is a huge boon.
#4 - Speeder
One of the best aspects of boats in GTA Online is that they're not that expensive in relation to their top speed.
The Speeder is the fourth fastest boat in GTA Online, but it only costs $325,000. Its top speed is 68.25 mph (109.84 km/h), although the game displays it as 82.64 mph (133 km/h).
#3 - Jetmax
Unfortunately, the Jetmax is the prime example of a boat that goes slower than what GTA Online displays. The game displays it as going 83.39 mph (135 km/h), but it actually only goes up to 70 mph (112.65 km/h).
Even if it isn't as impressive as other vehicles' top speed, the Jetmax is still the third-fastest boat in GTA Online, and it only costs $299,000.
#2 - Weaponized Dinghy & Dinghy
As one is the weaponized version of another boat, it is only fair to include them together in the same entry.
The Weaponized Dinghy isn't an upgrade to the regular Dinghy, so players have to purchase it entirely ($1,850,000 versus the original's $166,250). Still, its top speed is 71.50 mph (115.07 km/h), which is the second-fastest in GTA Online.
#1 - Longfin
Players looking for speed by the sea should seek the Longfin. It's the fastest boat in GTA Online based on top speed. Its true speed goes up to 122 mph (196.34 km/h), making it the premier option for players seeking a speedy exit by the sea.
Its top speed is terrific and isn't too much slower than the top aircraft in the game, although its price of $2,125,000 might drive away some poorer players in GTA Online.