Idaho's high desert and the Dalmatian coast feel worlds apart, and the journey between them is a study in patience rewarded. There's no nonstop, so booking business class from Boise to Split means routing through a major domestic gateway before crossing the Atlantic — and the choice of connection matters enormously. Delta, American, and United all serve this corridor, and the fact is that none flies direct: expect a domestic hop from Boise to a hub like Seattle, Minneapolis, or Salt Lake City (Delta), Chicago or Dallas (American), or Denver or Chicago (United), followed by a transatlantic leg into Frankfurt, Munich, Zurich, or a similar European hub, then a short regional connection down into Split.
Having flown this puzzle repeatedly, I favor routing through Chicago on American Airlines' Flagship Suite-equipped 777s or Delta's Minneapolis/Amsterdam pairing using their Delta One Suites on the A330-900 or A350 — both offer genuine door-closing privacy for the long transatlantic sector, which is where you want your premium hours banked, since the intra-European connector to Split is typically a narrowbody with a recliner-style business seat, not lie-flat. My insider tip: build in at least a 90-minute buffer in Frankfurt or Amsterdam for the SPU connection, since Croatia-bound flights often depart from remote satellite gates requiring bus transfers, and Split's own airport gets delightfully congested with charter traffic in peak summer.
Seasonality here is pronounced — Split is a Mediterranean summer magnet, so April, May, September, and October deliver the best combination of pleasant weather, thinner crowds, and more attainable business class award and revenue space, particularly on the Delta and United transatlantic legs. Because pricing and award availability on this three-carrier, multi-connection route shift constantly depending on which hub and aircraft you're routed through, it's worth setting continuous fare alerts rather than checking sporadically, so you can pounce the moment a strong Boise-to-Split business class itinerary opens up.
