Port could be a dark horse in the race for the Thai League 1 title in the upcoming season, which kicks off on Friday.
Port were the busiest team on the final day of the transfer market, which closed at midnight on Monday.
They signed two players -- defenders Kevin Deeromram from Ratchaburi Mitr Phol and Worawut Namvech from Chiang Rai United.
Thai-Swedish left-back Kevin had been expected to join SCG Muang Thong United but was instead unveiled by Port chairwoman Nuanphan Lamsam on Monday night.
His transfer fee was reportedly 40 million baht.
"I hope they both play well and help us end the season in a good position,'' said Nuanphan, who is also manager of the women's national team.
Kevin, who joined Ratchaburi last season, played 25 league matches and scored one goal for the Dragons.
He played for Sweden's U14 and U19 teams but chose to play for Thailand at the senior level.
He made his Thailand debut in a friendly against Uzbekistan last year.
The 20-year-old, who was born in Stockholm, was also a member of the Thai U23 team that won the SEA Games gold medal last year.
Earlier, Port signed Dragan Boskovic, Thai League 1 top scorer last season, from Bangkok United.
Port, who finished ninth last term, will open their 2018 campaign at home to Pattaya United at their PAT Stadium.
Port, meanwhile, loaned German striker Bajram Nebihi to FA Cup champions Chiang Rai United.
The Beetles needed a new striker after their new forward Gilberto Macena is ruled out for months due to injury.
Nebihi joined Port Ubon UMT but his name was not included in the list of players for Thai League 1 so he decided to move to Chiang Rai.
Meanwhile, Muang Thong United, last season's runners-up, suffered a huge blow as striker Adisak Kraisorn is unlikely to play this year, coach Totchtawan Sripan said yesterday.
Adisak was injured while playing for Thammasat University against Chulalongkorn University in their annual football match on Saturday.
"He will be out for eight to nine months,'' Totchtawan said.
The Kirins have lost their top striker Teerasil Dangda, who joins J-League club Hiroshima Sanfrecce on a one-year loan deal, and Totchtawan admitted that the team would be affected by Adisak's absence.
However, he said Muang Thong still have other forwards including new signings Jakson Coelho and Chenrop Samphaodi.