Air. Helsinki-Vantaa (HEL), 20 km north of the centre, is Finland's main hub and the home of Finnair. The airport train (lines I and P) runs to Central Railway Station every 10 minutes, taking about 30 minutes. A one-way ticket (€4.60) covers any local transport for 90 minutes.
Sea. Helsinki is one of the busiest passenger ports on the Baltic. Silja and Viking Line run overnight ferries to Stockholm; multiple operators (Tallink, Eckerö, Viking) run fast daytime ferries to Tallinn in Estonia — 2 hours, and cheap enough that Tallinners day-trip to Helsinki for shopping. Finnlines serves Travemünde in Germany; St Peter Line runs to St Petersburg (visa-free for short visits, when the service is operating).
Train. The Allegro high-speed trains to St Petersburg have been suspended since 2022. Domestically, VR trains run from Helsinki Central to every major town in Finland — Turku, Tampere, Oulu, Rovaniemi — and overnight sleepers go as far as Kemijärvi in Lapland.