The answer
Take the Line M4 metro from the station at the eastern end of Terminal 2 — €0.80 tapped onto a contactless bank card at the gate, about 20 minutes to Serdika. Trains leave from 05:21 weekdays (05:26 weekends) until 23:38 (23:46 weekends).
The airport station sits inside the ordinary city fare zone and the gates take bank cards, so there is no airport surcharge and no ticket to buy — and the same card caps a day of daytime travel at €2.00.
Landing at Terminal 1? There is no metro there — the free inter-terminal shuttle runs 24/7, every 20–40 minutes, to Terminal 2.
Landing after 23:38? Night bus N4 serves both terminals from midnight to 04:00 on a €1.00 night pass.
⚠️ The traps (walk past these)
Terminal 1 has no metro — and the low-cost split is not what you expect
The Sofia Airport metro station is inside Terminal 2, at its eastern end; Terminal 1 passengers must take the free inter-terminal shuttle first, which runs 24/7 every 20–40 minutes. The carrier split is counter-intuitive: Wizz Air and easyJet use Terminal 1, while Ryanair and the network carriers (Lufthansa, British Airways, Bulgaria Air, Turkish Airlines) use Terminal 2.
Do this: check the terminal on your boarding pass and add up to 40 minutes if you land at Terminal 1
The ticket machine at Terminal 1 arrivals is the wrong channel — and is still described in levs
The airport's own transport page says the vending machine at Terminal 1 arrivals works with Bulgarian levs and coins and sells tickets valid only for buses 84, 184 and 384. The lev stopped being legal tender on 1 February 2026, a month after the euro replaced it at 1.95583, so do not count on feeding a machine or arriving with lev cash.
Do this: tap a bank card, phone or watch on the metro gate or the blue reader in the bus and skip the machines
Anyone who approaches you in arrivals is not the taxi rank
SOF Connect names Yellow! as its contractual taxi operator and warns on its own transport page: 'We recommend that you do not use taxi services offered outside the office of the taxi operator or in front of the terminal to avoid the risk of abuse.' Drivers working the baggage belts quote flat fares for a €10–15 ride.
Do this: walk to the Yellow! office inside arrivals or the signed rank outside, and check the plate against your booking
The meter has a legal ceiling of €1.24/km by day — read the windscreen sticker
Sofia Municipal Council fixes both the minimum and the maximum per-kilometre rate: €0.73–1.24 by day and €0.84–1.52 at night in 2026. Anything above the maximum is not a legal tariff. The council has already approved a 5.3% rise from 1 January 2027, to €0.77–1.31 by day and €0.89–1.60 at night.
Do this: read the rate sticker before your bags go in and refuse any car quoting above the ceiling
The airport is being rebuilt: Terminal 3 works start in autumn 2026
SOF Connect closed €450 million of financing in 2026 and construction of Terminal 3 starts in autumn 2026, running about five years to April 2031, with Terminal 1 closing once it opens and Terminal 2 refurbished alongside. Expect changing kerbs and access roads.
Do this: allow extra time at the kerbside and check your terminal on the airport's live departures board