There are several open top bus sightseeing tours in and around Belgrade, featuring the top attractions as well as many less known.

Hop on, Hop off sightseeing tour (Belgrade open tour)

Hop on/off bus24-hour and 48-hour tickets give you the opportunity to visit Belgrade on board our green buses, feel free to move through the city centre just hop-on hop-off as you like for the validity of the ticket.

http://www.belgradeopentour.com/index-en.asp

Panoramic Sightseeing tour (BS Tours)

City sightseeing from an open top tourist bus takes about 70 minutes and it is available from April to October, every day except Monday. Start times are 11:00 am and 1:00 pm from Nikola Pašić Square.

Ticket price is 500 din., 300 din. for children under 12 years.

http://www.bstours.rs/en/sightseeing/

Seasonal Avala tour

http://www.lasta-turizam.com/ponuda/individualna-putovanja/open-top-ture/sezonska-linija-qlastinimq-otvorenim-autobusom-na-avalu/menu-id-428.html

Belgrade Monasteries tour

http://www.lasta-turizam.com/ponuda/individualna-putovanja/open-top-ture/manastiri-beograda/menu-id-428.html

Belgrade Monasteries II tour

http://www.lasta-turizam.com/ponuda/individualna-putovanja/open-top-ture/manastirska-tura-otvorenim-autobusom-ii/menu-id-428.html