Never been on a horse myself, except maybe on a fair when little, but when on Iceland we did a mtn-taxi tour we picked up a French couple on a horse farm. They were new to riding and were very positive and I believe Icelandic hoses are calm and suitable for beginners/learners. I believe the woman who helps with our economy stuff at work have been too, I can ask next time she's in if your interested.
Less likely to be combined with beach and bathing than Spain but on the other hand while kids are riding ..