Effective March 1, all travelers 12 and older who completed their primary vaccination series more than five months ago will be required to present proof of booster prior to embarkation.
Lindblad accepts any FDA-recommended vaccine: Pfizer, Moderna or Johnson & Johnson (Janssen). Boosters can be received any time prior to embarkation. For non-US travelers, the line will also accept Astra-Zeneca. Those with different WHO-recommended vaccine should check with their expedition specialist when making a reservation.
The line's full COVID protocols are here.