Malmo's Sturup Airport handles no widebody long-haul traffic, which is the essential fact worth knowing before you book: there's no nonstop option for business class from Boston to Malmo, and every itinerary routes through a European hub before a short connecting hop on SAS or another carrier's regional jet. That reality shapes the entire trip, and after flying this corridor repeatedly, I've settled on SAS via Copenhagen as the most sensible routing — Copenhagen is barely a 40-minute onward journey or a scenic train ride across the Öresund Bridge into Malmo itself, making it arguably more convenient than connecting through Stockholm. SAS flies A330s or A350s on the Boston–Copenhagen sector with their newer business class flatbeds featuring direct aisle access on the A350s, a real upgrade over the older staggered configuration still found on some A330 rotations, so it's worth checking equipment before locking in a fare.
Lufthansa and KLM offer viable alternatives if SAS availability is tight, though both require a second connection through Frankfurt or Amsterdam respectively, adding time but often opening up better award space. Lufthansa's Frankfurt hub gives access to their business class cabins on the 747-8 or A340, though Allegris-equipped aircraft aren't yet common on the Boston route, so don't count on that specific product. KLM via Amsterdam is a strong backup, particularly given Schiphol's efficient transfer process — my insider tip here is to request a window seat on the KLM 787 in row 7 or 8, which avoids the galley noise that plagues rows further back and makes the tight Amsterdam-to-Malmo connection feel less rushed.
Summer shoulder months — May through September — consistently bring the best premium cabin availability and pricing on this Scandinavia-bound routing, largely because Scandinavian leisure demand peaks then, ironically loosening up business class award seats as airlines add capacity. Given how much these three-carrier itineraries fluctuate week to week, setting up fare alerts specifically for this Boston-Malmo corridor will save you from manually hunting through Copenhagen, Frankfurt, and Amsterdam routings every time you want to travel.