The airline said the Boeing 737-800NG aircraft has been leased from Malindo Air which is owned by the Indonesian Lion Air Group and based in Malaysia.
It has now gained regulatory approvals from the civil aviation authorities in Australia, New Zealand, Samoa and Malaysia.
Samoa Airways CEO, Tupuivao Seiuli Alvin Tuala, said he was delighted to resume international jet services between Samoa, New Zealand and Australia.
Passengers from at least eight flights had to be re-routed to other flights over the past week after the lease expired on Samoa's plane and a replacement could not be found due to the global grounding of MAX 8 aircraft.
Seiuli thanked the airline's customers and trade partners for their patience.