The orange city buses are run by Autotrolej. Rijeka’s central bus stops are at Jelačićev trg and Delta Terminal. They connect all the points you need, the city centre with Trsat and other suburbs, plus resorts on the Opatija Riviera and Kvarner coast, and places inland such as Kastav. Buy tickets in any news kiosk for 2,80 - 5,20 €; they are valid for two trips on within the city, stamp your ticket on entry. Tickets bought inside the bus for 2,00 - 3,50 €, are valid for one trip on any city route. For timetable information check https://voznired.autotrolej.hr/