To my knowledge there is no shore diving on Roatan. But there are dive sites that are close to shore, so close that you could swim out, if only you could find someone to rent you the gear. The best part about the sites that are off the beach in WEst Bay is the reef top. None of these sites have the famous swim-thrus and caves that make R so great. No swim-thrus until you get around to Blue Channel, well north of West Bay. A site off West Bay called Mandy's Eel Garden has lots of garden eels, and that's cool, but not as spectacular as what you will see from a boat. There are probably 7-8 shops in West Bay and another dozen in West End, and none of them will rent gear for shore diving, as far as I know.
Surely there are people who do manage to get themselves out to dive without a boat, but this is a very uncommon practice. Never seen anyone doing it. Besides by avoiding the boat, they would be missing out on the spectacular sites to the north and east of Blue Channel.
What there is along West Bay is easy snorkeling close to the beach. But this is getting degraded as more and more people stand on the reef or kick it. The further north you go, the more pristine the reef.