Aeroporto Internacional de São Paulo-Guarulhos is Brazil’s largest and busiest airport, and one of the busiest in South America. Since 2014, the airport has operated with three terminals, with Terminal 3 having been constructed before the FIFA World Cup. Terminal 1 is exclusively used by Azul Linhas Aéreas, one of the airlines founded by David Neeleman, founder of JetBlue , Breeze Airways, and several other carriers.
Terminal 2 is primarily used for domestic flights with LATAM Brasil , GOL Linhas Aéreas, and Passaredo. Some international carriers operate international flights at Terminal 2, like GOL, LATAM, Aerolíneas Argentinas, Aeroméxico, SKY Airlines, JetSMART, TAAG, and more. Terminal 3 is used exclusively for international flights by most large international carriers like the big three from the United States (United Airlines, American Airlines, and Delta Air Lines), British Airways, Air France, Emirates, and more.
Terminal 1 Terminal 1, the smallest of the three, has only one lounge. The W Premium Group is one of the largest airport lounge groups in Brazil, now with 16 lounges in 11 airports, and is the sole operator of T1. The lounge is small but enough to accommodate all the flights on a daily basis.
I have visited the lounge several times and have never seen it completely full. Terminal 2 Terminal 2 has ten lounges, The Lounge São Paulo, W Premium Lounge - The West, Urban Cowork Airport Lounge (landside), Advantage VIP Lounge, GOL Linhas Aéreas Lounge.