The cheapest way to the airport. The Arlanda Express is 43 minutes quicker for SEK 297 more, which is not worth it at this party size.
Bus 583 via Marsta
58341 · SLPickup, hours & luggage
Boards at. Stockholm City, on the commuter train towards Marsta, then bus 583 to Sky City
One ordinary SL single covers the whole journey — bus and train, one ticket, no passage fee, because the fee applies only to the station gates and this route never uses them. The reduced fare is SEK 26, and under-18s pay it without any supplement.
Luggage. A city bus and a commuter train. There are no racks and you keep your bags with you.