Can You Get from London Jamaica by Boat? No—It's a Railway Station

London Jamaica is a London Overground station in the Jamaica Road area of Bermondsey (Travelcard Zone 2). It has no water access; the Thames is ~300 m north but no pier serves the station.

If you meant Kingston, Jamaica (the Caribbean capital), sea travel from London takes 12–16 days by cargo ship or ~9 hours by air. No regular passenger liner exists.