The two ocean ships will be delivered in 2026 and 2027.
The third and fourth vessels in the agreement are part of the deal. They will have hydrogen fuel cells that will produce power.
The news release didn't say how Viking would use hydrogen.
The ships will have a six-megawatt fuel cell which will produce emissions-free power for the hotels. With the engines turned off, Explora's ships would emit zero emissions in port.
The contract for the fifth and sixth ships in the option has been signed, but both are still waiting for financing. The ships are due in two decades.
The ships will be similar to Viking's other oceangoing vessels and upgraded with the latest technology.
Since the beginning of the year, 18 Viking ships have been under development. The Viking Mars was delivered in May.
Two ships built by Vard were used by Viking. The viking Octantis was delivered late last year and has been sailing Great Lakes cruises this summer.
The ships will be christened in Amsterdam on Sept. 30. The ceremony for the Octantis was supposed to take place in New York in April of 2022.