Del Olmo also earned 51 caps and 3 goals for the Mexico national team. He made his international debut on 29 June 1993 against Costa Rica, in a 2–0 victory. Under coach Miguel Mejia Baron, del Olmo represented Mexico in that year's CONCACAF Gold Cup and made the squad for the 1994 FIFA World Cup, where he played in Mexico's first-round games against Norway, Ireland, and Italy. He also appeared at the 1995 Copa América and 1996 CONCACAF Gold Cup, as well as several qualifiers for the 1998 FIFA World Cup, but he missed out on Manuel Lapuente's final World Cup squad. After a long absence from the team, del Olmo was recalled at age 32 by Enrique Meza in 2001. He earned his last cap on 16 June 2001 in a 2–1 loss at Estadio Azteca to Costa Rica in a qualifier for the 2002 FIFA World Cup.