Plus, all bookings in the sale receive an evening of free specialty dining and are eligible for a low $100 deposit.
The line's 50th anniversary was in 2015; a company spokeswoman said the sale continues to celebrate its founding.
Passengers booking an inside or ocean-view stateroom get up to $300 on-board credit per stateroom. Those booking a balcony, mini-suite or suite receive up to $600 in on-board credit per room. All bookings receive an evening of free specialty dining including third and fourth persons per stateroom.
Examples of Anniversary Sale deals include a seven-day Alaska cruise priced starting at $599 per person in an inside room and $1,399 in a balcony room, plus up to $300 in on-board credit.
An 11-day Scandinavia and Russia cruise is priced from $1,799 per person in an inside room and $2,099 in a balcony room, plus up to $400 on-board spending money.
A seven-day summer Caribbean cruise starts at $699 per person in an interior room and $1,199 in a balcony room while the on-board credit ranges up to $300.
The Anniversary Sale is open to residents of the US, Canada, Puerto Rico, Mexico, Bermuda and the District of Columbia who are at least 21.
More information is here.