[2] After two years in Mattersburg, he joined German side FSV Mainz 05 in January 2016.

[3] In his first full season in Mainz, Onisiwo played in the UEFA Europa League and finished as 3rd in group stage.

[5] On 2 January 2025, Onisiwo returned to Austria and signed a contract with Red Bull Salzburg until 30 June 2026.

[7] He made his debut for the senior Austria squad as a substitute, in a friendly against Switzerland in November 2015.

This biographical article related to association football in Austria, about a forward, is a stub.