The Terminals That Anchor the Region
Leon's Central de Autobuses sits on Boulevard Adolfo Lopez Mateos in the east of the city, about 20 minutes by taxi from the Historic Centre and the Poliforum. Primera Plus, ETN and Futura all run from here, so you rarely need to queue for a second operator. Guanajuato's terminal is on Carretera de Cuota Silao-Guanajuato, roughly 15 minutes by local bus or taxi from the Jardín de la Unión; city buses run the route until late evening.
Querétaro's main terminal is on Avenida Constituyentes Poniente, close to the Estadio Corregidora and around 25 minutes from the historic centre on a local bus. San Miguel de Allende's terminal is a short, cheap taxi ride from the Parroquia and the Jardín Principal. Because primary operators share terminals, a single booking counter covers several companies, and you can compare departures on the spot rather than online.
Times, Frequencies and What to Book Ahead
Leon to Guanajuato is around 50 to 60 minutes on the direct toll-road services, with departures running roughly every half hour from early morning to evening. Leon to Querétaro runs about three hours, and Leon to San Miguel de Allende around two and a half. Guanajuato to San Miguel takes about 90 minutes via Dolores Hidalgo, and Guanajuato to Querétaro roughly two hours. Second-class services stop more often and can add 45 minutes to any of these.
Primera Plus and ETN are the comfortable choices, with assigned seats, air conditioning and, on longer runs, a restroom. ETN tends to cost more; Primera Plus is the sensible middle. Second-class lines such as Flecha Amarilla are cheaper and fine for short hops but slower. In the days around Easter and the last week of July, seats to San Miguel and Guanajuato fill quickly, so buy 24 to 48 hours ahead. Ask at the counter for the next direct departure rather than the next bus.
Doing It Without a Car
For San Miguel de Allende, take the bus and use taxis or walking. The town is compact and hilly, and parking near the Jardín Principal is scarce and expensive. Guanajuato is even more car-hostile: the city runs on tunnels and stairways, so leave the vehicle and use the local bus to the terminal and the funicular up to the Pipila monument. Leon is walkable in the centre, though the Poliforum and the terminal sit far enough apart to warrant a taxi.
If your trip circles Mexico City, Leon, Guanajuato and Querétaro, buses make the loop easy; Mexico City's Terminal del Norte and Terminal Observatorio connect to Querétaro and Leon respectively. I would base two nights in Guanajuato, two in San Miguel and three in Querétaro, and skip León unless the Poliforum has an event. Querétaro's historic centre and the Peña de Bernal are worth the extra day.
When to Go and What to Skip
The dry months from November to March are best for this loop: cooler days in Guanajuato and less rain on the Querétaro highways. April and May heat up, and June to September brings afternoon downpours that can slow buses on the mountain stretches. December and Easter week bring domestic crowds and higher hotel rates; book both transport and rooms early if you travel then. Weekday departures are noticeably quieter than Friday and Sunday.
Skip night departures for short hops; you will arrive tired and pay for a room you barely use. Do not buy from touts at the terminal entrance; use the official counters or the operator's own app. For San Miguel, book a hotel within walking distance of the Jardín Principal rather than on the highway side, where taxis add cost and time. Reserve through a local partner, confirm the check-in window, and carry small change for terminal taxes and local buses.