San Matías is in the department of Santa Cruz close to the border of Brazil. The principal reason to come is to cross or come from the Brazilian border.
From Santa Cruz, two buses leave daily at 6:30pm and 9:00pm. The journey duration is variable, especially depending on the season. Some of the roads from Santa Cruz are dirt and can take more time in the wet season. The departure at 6:30pm is a normal bus and is 100 bolivianos [September 2017]. There are various stops along the way and the journey duration is variable, in the dry season approximately 16 hours.
The 9pm departure from Santa Cruz is a full cama luxury service, costing 200 bolivianos. They advertise that they arrive at 10am.
From the bus terminal, you can take a taxi to get your passport stamped at migration and then driven to the border at Corixá. This costs approximately 50 bolivianos. The time taken depends on the line at migration, but the taxi journey is approximately 15 minutes. From the Brazilian border, there is a bus service that leaves for Cáceres. This takes approximately 1.5 hours, costs 25 reais and has services every couple of hours until approximately 5pm. In Cáceres you need to get your entry stamp at migration.