During the high season, there are one or more karaoke shows each night in Mazatlán. Most karaoke shows in Mazatlán will have both English and Spanish songs to sing. The shows operate in the same manner as karaoke shows in the US or Canada, i.e. you write down your song request, hand it in, then wait to be called up to sing!
For the 2017-2018 season, the hosts that have multiple shows are Roberto and his daughter Diana, and Diana and Robert Hawes. There are a number of other hosts who only host one show a week. There are karaoke shows in the Golden Zone, Sabalo Country, Downtown, and Cerritos. The main restaurant/bars that have karaoke are Margaritas, El Cid Castilla bar, El Cid Marina bar, Last Drop, La Catrina, and Friends Diner. The Saloon which had a long running Saturday show closed down in the spring of 2017 so obviously there are no more shows there.
There is a complete listing of karaoke shows in Mazatlán (and all over the world) here: Complete Mazatlán Karaoke Schedule on KaraokeSchedule.com