Marin, 27, beat Chinese Taipei's top seed Tai Tzu Ying in straight games in an ominous display of form as she prepares to defend her Olympic title later in the year in Tokyo. Tai was limited to a single digit score in the first game and while she fought hard in the second, Marin ended up winning the match 21-9, 21-16.
This was Marin's seventh win in 16 meetings against Tai.
Axelsen, meanwhile, recorded his second consecutive tournament win with a 21-14, 21-14 win over Hong Kong's Angus Ng Ka Long. Axelsen had earlier won the All England Open Championship in March.
Indonesia's Greysia Polii and Apriyani Rahayu beat Thailand's Jongkolphan Kititharakul and Rawinda Prajongjai 21-15, 21-12 to win the women's doubles final. Taiwan's Lee Yang and Wang Chi-Lin beat Malaysia's Goh V Shem and Tan Wee Kiong 16-21, 23-21, 19-21 to win the men's doubles title.
In the mixed doubles, top-seeded Thai pair Dechapol Puavaranukroh and Sapsiree Taerattanachai beat Indonesia's Praveen Jordan and Melati Daeva Oktavianti 21-3, 20-22, 21-18.