The Coast Guard Assistant Commandant for Prevention Policy has published Marine Safety Information Bulletin 02-21 Change 4 “COVID-19 Safety Requirements in the Maritime Transportation System”. Change-4 to this MSIB reflects that the CDC has issued no new guidance for maritime travel and continues to require mask wear in indoor areas of conveyances and US transportation hubs. All previous guidance outlined in MSIB 03-21 CH-3 remains in effect.
Source: USCG
Link: MSIB: COVID-19 Safety Requirements in the Maritime Transportation System: Change-4