Rio de Janeiro and Sao Paulo are on the same time. Both cities use Brasilia Time (BRT, UTC-3). When it's 12:00 PM in Rio de Janeiro, it's also 12:00 PM in Sao Paulo.
Brazil no longer observes daylight saving time (since 2019), so these cities remain synchronized year-round.
Any time works! Since both cities share the same time zone, you can call during normal business hours (9:00 AM - 6:00 PM) without any conversion needed.
Rio de Janeiro and Sao Paulo are Brazil's two largest cities, just 430 km apart. The air shuttle between them (Ponte Aerea) is one of the world's busiest routes, with flights departing every 30 minutes.