From Rio

There are 7 daily buses from Rio - Company Viação 1001 - * three with air conditioning

Rio - Buzios
6:04 / 8:04 / 10:04 / 12:04 / 14:04 / 16:04 / 18:04 / 20:04
Buzios - Rio
6:00 / 8:00 / 10:00 / 12:00 / 14:00 / 16:00 / 18:00 / 20:00
Somente aos Domingos: 20:30
Duration: 3 hours 

From São Paulo

Fridays 21:45 (air con)
Duration: 9 hours

Also São Paulo - Cabo Frio - daily, 22:30h - viação 1001 (from Cabo Frio to Buzios it's just 20 km, take a regular bus or alternative van just across the avenue. Comes every 20 minutes)

Important:

For season and hollydays some extra departures are offered 

Viação 1001 Phone numbers: 

National: 03003131001 

Búzios:  2623 2050 

From Macae

Viação Macaense (0800 246555) daily departures

Macae - Buzios
7:40 / 15:20
Buzios - Macae
10:30 / 17:45
Duration: 1:40 m

You will find excellent roads on your way to Buzios - the bridge and the Via Lagos are private, keep some change at hand. Keep atention to speed limits - radars ares all around and fees are high.

Leave Rio by Rio-Niterói bridge, keep left at the end of the bridge and follow indications to either "Região dos Lagos" - "Cabo Frio". Follow the main road for around 1 hour paying atention to the city of "Rio Bonito" indication, it's close to the entrance to "Região dos Lagos" at your right hand. It's a private road with a big, complete and clean "pit stop" place.  After 27 km you should be seeing Araruama Lagoon and a little later the entrance to "São Pedro da Aldeia". Pay atention to turn left at the Atlantic Gas station to take the road to Búzios. Follow the road till you see a vertical indication "Até Q Enfim" (Finally), it's time to turn right and come straight to Buzios.

Duration: aproximately 2 hours

Rio - Buzios
18:00h 
Buzios - Rio
18:45

Duration: 25 minutos