In reply to Mattilda:
Since starting my sea kayaking addiction nearly 3 years ago this is always something that's been on my mind. There aren't many crags in the UK where access by car and foot wouldn't be easier than by kayak, not that that's a reason not to do them - thanks up-thread for some excellent suggestions in Scotland.
Big tidal ranges around many crags in Wales and the SW could make landing and stashing your kayak while you climb and ab off, and as others have said rocky landings can add to the complexities. Unfortunately climbing is not allowed on many of the off shore islands around Pembroke due to bird restrictions.
One option for sport climbers would be to paddle the short distance from LLandudno to the Diamond on the Little Orme, a lot easier than the arduous walk and via-ferrata approach that I understand has recently been set up. However I was never quite good enough to climb there, and time spent sea kayaking has further eroded by climbing grade (as someone on UKC predicted it would when I started!)
One trip that would really appeal is a paddle from Bara to the Great Arch on Pabbay, do a route, ab back down and paddle back to Bara for a well earned pint, particularly as the walk from the Pabbay campsite can be quite arduous.
My composite kayak is rather small and nimble Rockpool Isel - optimum for day trips in conditions rather than expeditions. I have packed it for a week's camping in Scotland but no room or freeboard left for climbing gear.
I expect there's lots of opportunities for kayak access to remote crags and first ascents in NW Norway and Lofoten - I'm hoping to do a combined kayaking and climbing trip up there next year. I'd have to buy a larger expedition type kayak (n+1!) or hire something suitable locally.
Post edited at 16:40