Santis tallied 32 goals in 124 appearances across all competitions, winning the 2021 CONCACAF League and Liga Nacional de Guatemala 2021-22 Clausura with Comunicaciones.

[8] In January 2024, Oscar Santis signed with Georgia’s Erovnuli Liga club Dinamo Tbilisi on a two year contract with a possibility of extension.

[11] On 3 April 2024, Santis made his first contribution to a goal in Europe, assisting teammate Vakhtang Salia in a 2-2 league draw against Dila Gori.

On 26 December 2024, Antigua and Oscar Santis announced that he will be joining the team once again on loan for the 2024–25 Liga Nacional de Guatemala Clausura.

[18] On 4 June 2021, at the 2022 World Cup qualifying match against St. Vincent and the Grenadines, Santis scored his first senior goal for Guatemala in a 10–0 victory.