Dont laugh...

[matata]

We were out last w/e off Bardsey approx three miles from nowhere heading back to Pwllheli 20knots when 200m straight ahead of us a big big fish jumped clear out of the water in front of us. We both saw it very clearly as it was quite calm. Ive seen loads of dolphin/ porpoises around there and this was not one of those. As it lept out it did a roll with a big splash and you could see its white belly.If a dolphin/porpoise is say five foot long this guy was probably 10 feet. We both poo'd ourselves! any suggestions what it was ? Nik

[Pikey Dave]

You're gonna need a bigger boat😳


Lions led by donkeys

[Bern Hanreck]

Breaching Porbeagle Shark perhaps ?

www.orma.com/sea-life/porbeagle-shark

[Stuart1975]

atlanticn whit sided dofin ? they get up to that big

[jyasaki]

Most fish generally only break the surface when chasing prey. While it could be a fish (I'm not familiar with your list of fish species), there likely aren't a whole lot that get that big.

I'd suspect some kind of marine mammal - dolphin, porpoise, sea lion (if your eyesight is suspect), even a small whale.

jky

[slate1234]

there was something on the welsh news last week: People have been urged to keep an eye out for "unusual and enigmatic" whales off the Welsh coast after scientists were told about a number of sightings.
Long-finned pilot whales typically live in large groups in deep waters beyond the edge of the continental shelf in the Atlantic.

[Curlew]

My guess would be a bottlenose dolphin. Length around 12 feet, white underside and jumps a lot.

[spartacus]

My money is on a dolphin, but outside chance could be minke whale which has white underbelly. Never seen one breach though. Bad enough when they just come up for air next to the boat!

Porbeagle shark. Yes white underbelly, but breaching? Never seen one and don't plan to any time soon.

[willk]

Male basking shark breach occasionally.

[BettySwallocks]

Did it look like this?