All beach hotels will have access to boats that can take you snorkelling on the reef.
The half day snorkeling outing to the local reef (which is 200-600 meters out depending on where you are) only costs around 10 USD. They use small glass bottom boats. As mentioned you can book the excursion from any hotel or beach bar, it's the same boats for everyone, so it doesn't have to be a factor in your choice of hotel.Edited: 17 October 2018, 09:20
i f i am in mombasa i would have to use the ferry to go to ukunda,.,.
ferry is a disaster
That's not a very helpful statement. The OP is coming from Poland and I believe a Polish charter company does flights to Mombasa. In that case he'd have to put up with the ferry but it isn't fair to paint it as dangerous.
On the other hand, he may land in Nairobi to conduct a safari and in that scenario a flight to Diani would be a good and affordable option. In fact it's faster to access Diani from Nairobi than it is to reach Watamu. I'm not playing down Watamu's appeal, just setting out the full options.
Thank you very much for engagement.
I have not suspected that there may some ferry problem arise :) Believe me, I am not afraid of ferries :) Traveling ( for me ) is not only occasion to spend time in comfort but also to gain some local atmosphere. I.e. I will forever remember local bus ride from Puerto Princessa to el Nido ( Palawan Philippines ). It still scares s...t out of me :D.
As KronickR suggested I will take flight to Nairobi. Then 3-4 days safari ( currently negotiating with local travel companies mentioned on Tripadvisor ) and be fetched do Diani Beach ( or Wanatmu ). Spend some leisure time. Fly home from Mombassa afterall.
I am still thinking which place is better for snorkeling: Watamu or Diani Beach.Edited: 21 October 2018, 17:20
depends on the time of the day you get the ferry. i usually pay a guy to be my guide when i go that way now,.
we stayed in malindi for 6 days following our 2 week safari. snorkeling was very good in the marine park-octopus, sting ray, etc.