Tourism Minister Manohar Ajgaonkar flagged off the buses, being operated by Pune-based private group Prasanna Purple, yesterday.
"Popularly called the hop-on-hop-off coach service, the red buses will take tourists to popular sightseeing spots in and around the capital city, Old Goa, Miramar and Dona Paula to begin with," a senior tourism department official said.
The open-roof double and single decker buses will offer holiday-makers an opportunity to explore Goa with flexibility and comfort, he said.
Tourists can buy a pass - valid for 24 hours - and board a bus to visit their locations of interest. They can get off at any spot and later board any of the following HOHO bus.
The buses will start from the tourism department's headquarters and take travellers to popular sites like Panjim Church, Palace of Arch Bishop, Miramar Beach, Goa Science Centre, Dona Paula, Kala Academy, Bhagwan Mahaveer Garden, Panjim Market, river cruise point and Goa State Museum, among others, he said.