ILB requested to assist 2 Jet skiers reported aground in the Swale, ILB already afloat on exercise close to Queenborough Spit and proceeded into the Swale at 18:00. ILB arrived on scene 18:30 to find the jetskis high & dry on the mud, some way from any navigable water or the sea wall. CG mobile units from the Island & Herne Bay attended and attempted to get to the 2 casualties with the jetskis. After some considerable effort by both the ILB crew & CG it became apparent that extracting the casualties across the mud was not a viable option and CG helicopter 163 was requested to assist. 163 arrived on scene 20:40 and was able to lift both casualties & CG personnel to safety, although it had to divert to Southend to refuel during the operation. All personnel ashore by 21:45, ILB released 22:05 & returned to station, being ready for service after cleaning by 23:30. Weather; E2.