Early career Having joined the ranks of Blooming as a teenager in the mid-1990s, Vaca made his debut in the
Bolivian Primera División on 12 December 1999, aged 21, in a 1–1 draw with his future club
The Strongest. On 4 August 2017, he made his 300th appearance for The Strongest in a match that included a hat-trick and the debut of three young players. Five days later, on 9 August, Vaca made his 50th Copa Libertadores appearance in a loss to
Lanús, becoming the goalkeeper with the most such appearances in Strongest's history. On 27 October 2018, he made his 297th appearance for The Strongest in a match against
Destroyers, surpassing
Luis Galarza as the player with the most appearances for the club. The following month, on 30 November, Vaca made his 300th appearance for The Strongest in Bolivian tournaments in a match against Bolívar, wearing the captain's armband in the absence of the red-carded
Pablo Escobar and helping his side to a 1–1 draw. On 30 September 2019, Vaca made his 400th appearance for The Strongest in a 6–1 league thrashing of his former club Blooming. He won the award for Best Goalkeeper of the 2019 season, in which he started in 51 of the 52 league matches, missing only one because of yellow cards accumulation. By late 2020, he was one of only three 40-year-old players in the Bolivian top-flight, the others being
Carlos Saucedo and
Martín Palavicini. On 13 March 2021, Vaca made his 439th appearances with the Strongest in a top-tier league match against Independiente, surpassing Escobar's tally of 438 to became the player with the most official matches in the club's history, and two months later, on 18 May, he made his 56th Copa Libertadores appearance for The Strongest in a 2–1 victory over Brazilian side
Santos, surpassing Escobar's tally of 55 to became the player with the most such appearances in the club's history. On 25 July, he started in his 41st Bolivian Superclásico against Bolívar, becoming, at the age of 42 years, 8 months, and 22 days, the oldest-ever player in the history of the Bolivian Superclásico, breaking a 53-year-old record set by
Víctor Ugarte in 1968, aged 42 years, 5 months, and 8 days. In early 2022, Vaca left the club after 11 years, having won 5 titles, including three Bolivian top-flight titles (2012–13, 2013–14, and 2016–17), and playing in 10 consecutive editions of the Copa Libertadores.
Royal Pari On 9 February 2022, the 43-year-old Vaca signed for
Royal Pari, with whom he played in the
2022 Copa Sudamericana, ==International career==