[3] Sequeira made his senior debut for Real Unión on 29 October 2017, in a 3–0 Segunda División B away loss against CD Tudelano.

[4] On 8 September 2020, Sequeira moved to Celta Vigo on loan for one year, being initially assigned to the reserves in Segunda División B.

[9] His debut came during a friendly match against South Korea in November 2022, when Sequeira came in as a substitute for Joel Campbell as Esteban Alvarado received a red card.

Sequeira's first instant of action as a goalkeeper for Costa Rica was also his first goal conceded, as Alvarado's red card also meant a close free kick eventually scored by Son Heung-min.

[10] During the Copa America of 2024, Sequeira kept a clean sheet vs Brasil, becoming the first Costa Rican keeper to do so in 64 years, he subsequently was honored with the player of the match award.