Hardly anyone talks about P4, but it is official SOF parking
Parking P4 sits inside the Sofia Airport complex as an economy option, but it gets almost no attention compared with the main T1 and T2 car parks. It is an official SOF facility, not a private off-airport lot, and pricing brackets usually come in cheaper than the terminal garages if you stay more than a couple of days. Think of it as overflow: basic, functional, and used most by infrequent flyers who wander past P1–P3 and keep driving.
Sofia Airport runs terminals T1 and T2, and P4 sits in the orbit of those, so you still need to factor in a short walk or shuttle to the terminal you fly from. Because there are no widely reported user reviews, assume minimal extras: no valet, no premium bays, and likely standard open-air surface parking. Payment at SOF car parks usually runs via ticket-at-barrier on entry, then pay-at-machine before exit, so arrive with a card or cash ready.
Information from SOF groups suggests economy lots like P4 target multi-day trips, often with a price drop after the first 24 hours. If the covered garages at T2 are full or too pricey, P4 becomes the backup that still keeps you on airport grounds, instead of pushing you to third-party lots farther from the runway line. Because the airport lists it as an economy product, plan on basic lighting and marked lanes rather than tight security patrols or cameras on every row.
Practical tip: build in an extra 15–20 minutes before check-in to find P4, park, handle payment machines, and reach T1 or T2 on foot or by shuttle, especially on early-morning departures.