The city centre is compact and walkable. The Archaeological Museum, the Roman Thermae, the cathedral, and the main pedestrianised shopping street are all within easy walking distance of each other. The sea garden starts a few minutes from the centre and runs south along the coast — walking its length takes the best part of an hour.
Trams and buses: Varna has a tram network (lines 1 and 2 are most useful for visitors) and an extensive bus system. Tickets are cheap and bought on board; drivers give change. The tram connects the train station with the sea garden area.
Taxis: Metered taxis are plentiful and inexpensive by Western European standards. Use the meter — don't accept a flat fare from a driver who doesn't offer to switch it on. Taxi apps (Yellow, OK Supertrans) give you predictable pricing.
Car: Useful if you plan to explore the surrounding coast — the resort towns at Golden Sands and Albena to the north, or the quieter villages to the south. Parking in the centre is metered and can be fiddly; most visitors do better without a car for the city itself.