José Martí International Airport, Havana: The sensible option is a pre-arranged shared taxi or private transfer straight to your casa particular in Trinidad: roughly 4.5–5.5 hours, usually about US$120–180 for a private car or less per seat in a shared car. The cheaper alternative is taxi to Havana’s Viazul terminal, then the Viazul coach to Trinidad (about 6–7 hours total from Havana, roughly US$25–30 for the bus); it is slower and schedules can change.
Abel Santamaría Airport, Santa Clara: Useful only if your flight schedule works. Pre-arrange a taxi/shared taxi through your accommodation for the 2.5–3.5-hour run to Trinidad; expect roughly US$60–100 per car, depending on demand and vehicle. Do not assume there is a reliable onward public-airport connection.
Jaime González Airport, Cienfuegos: Cienfuegos is the closest practical air gateway when flights are operating. A pre-booked taxi or shared taxi to Trinidad takes about 1.5–2 hours and commonly costs around US$40–70 per car. It is a better transfer than trying to piece together local buses, but CFG has limited and changeable service.
Trinidad Viazul bus terminal: Viazul is the realistic long-distance public-transport arrival, with connections that can include Havana, Cienfuegos, Santa Clara and Santiago de Cuba depending on the current timetable. Reserve online when possible and reconfirm locally: Cuban transport schedules and vehicle availability are not dependable enough to build a tight same-day plan around.