The Premier buses depart from the ADO terminal in Chetumal. The other Belizean buses depart from Nuevo Mercado (New Market). The ADO website is http://www.adogl.com.mx/
Here are the schedules for Chetumal to Belize buses...
1. Premier Lines (an affiliate of the Belizean bus company, National Transport Services) provides express bus service between Belize City and Chetumal. In Belize City, buses arrive at and depart from the Belize City Bus Terminal (commonly known as Novelo’s) located on West Collet Canal. In Chetumal, buses arrive at & depart from the ADO terminal, but they park at the Nuevo Mercado (New Market) when not at ADO. The buses are a bit better than the Bluebird school buses and some are first-class type; all have air-conditioning though it might not function. There are stops for passengers at Orange Walk and Corozal. http://www.nationaltransportbelize.com/
Depart Belize City: 6:00 am, 9:00 am and 11:00 am daily
Depart Chetumal: 10:45 am, 1:45 pm and 4:45 pm. Note: these times are Belize time; there will be a 1 hour difference when Chetumal is on DST.
Duration & cost: about 3 hours & BZ$16.00
2. EXPRESS BUS SCHEDULE – FLORES / BELIZE / CHETUMAL
Two Guatemalan bus companies, Linea Dorada and San Juan Express Bus Service, provide bus service between Flores, Belize City and Chetumal. In Belize City, buses arrive at and depart from the Belize City Water Taxi / Marine Terminal on North Front Street near the Swing Bridge. Buses operate on Sundays and public holidays. Not all buses are air-conditioned. The schedule below was in effect on 1 December 2008 but always confirm times before travel.
The agent in Belize for these bus lines is Mundo Maya Travel located beside the Marine Terminal. Phone: (501) 223 0457 / 223 1235. Email: firstname.lastname@example.org
FLORES TO BELIZE CITY (235 km / 146 miles / about 5 hours)
San Juan Bus departs 5:00 am daily: US$ 25.00
Linea Dorada departs 6:00 am daily*: US$ 25.00
San Juan Bus departs 7:30 am daily: US$ 25.00
* Departure of the Linea Dorada bus is sometimes delayed because it waits for a connecting bus from Guatemala City. It then stops in Santa Elena.
BELIZE CITY TO FLORES (235 km / 146 miles / about 5 hours)
San Juan & Linea Dorada depart 9:30 am daily: US$ 25.00
San Juan Bus departs 2:30 pm daily: US$ 25.00
BELIZE CITY TO CHETUMAL (161 km / 100 miles / about 3 hours)
San Juan Bus departs 10:30 am daily**: US$ 10.00
Linea Dorada departs 12:30 pm daily**: US$ 10.00
** These buses are not always punctual.
CHETUMAL TO BELIZE CITY (161 km / 100 miles / about 3 hours)
San Juan Bus departs 5:00 am daily: US$ 10.00
Linea Dorada departs 6:00 am daily: US$ 10.00
The Linea Dorada bus boards in the bus terminal. The San Juan bus boards outside the terminal.
3. National Transport Services (a Belizean bus company) also provides service to Chetumal. In Belize City, buses arrive at and depart from the Belize City Bus Terminal (commonly known as Novelo’s) located on West Collet Canal. In Chetumal, buses arrive at & depart from Nuevo Mercado. The buses are used Bluebird school buses; most of them are not very comfortable, not air-conditioned and are not well equipped to handle luggage, but they are cheap! There are a couple of air-conditioned buses that are used on some Express runs. The schedule below is an old one so check times at the terminal. The Express stops for passengers at Orange Walk and Corozal. The Regular stops anywhere along the route.
Depart Belize City: 6:45 am (Express), 7:30 am (Regular), 8:30 am (Regular), 1:00 pm (Regular), 5:30 pm (Express)
Depart Chetumal: 4:00 am (Express), 9:00 am (Regular), 2:30 pm (Regular), 3:30 pm (Regular), 7:00 pm (Express)
Duration & cost: the Regular is about 3.5 hours & BZ$9.00; the Express is about 3 hours & BZ$12.00.
4. COROZAL / CHETUMAL
Several bus companies (BBOC, Chell, Gilharry, NTSL, Russell, Tillett, T-Line, Venus) operate on this route.
Buses depart Corozal bus terminal every half hour beginning at 7:00 am; last departure at 8:00 pm.
Buses depart Chetumal Nuevo Mercado every half hour beginning at 4:00 am; last departure at 5:45 pm. Most, if not all buses, continue to Orangewalk & Belize City.
I don’t know the exact cost, but it’s about BZ$3.00 or $4.00 to Corozal.
Sometime in March 2009, the schedule will change. The departure times are not expected to change, only the operating times of each bus line.
This information is from the Corozal bus terminal supervisor, and is different from the schedules posted on the wall of the terminal.
-----------------------My wife, and I took the "collectivo" from Cancun Airport to Playa del Carmen. We stayed in Playa overnight - lots of hotels - the bus takes you right to 5th Ave. We then caught an early ADO bus - they leave on the hour- to Chetumal. NOTE = you do not catch the Chetumal bus at the same bus station you get dropped off at (too easy) - But its not far away - just ask someone (very friendly people) all over (Gringos, and Mexicans both). Anyway... when we got to Chetumal bus station- we ran into a fellow traveller - who knew there was a Belize bus ...we waited about 1 hour and hopped on it took us over the border to Corazol.
The buses cost... The colectivo from airport to Play del Carmen was $8 American. The Playa to Chetumal bus was 220 Pesos (about $20 American). The Belize bus was about $5 American. It was all very painless, and kind of fun - we have not really travelled by bus much. ADO buses are very good, no worries.
from the Belize Forums