**There is no scheduled passenger ferry from Europe to either Kingston or Port of Spain. But a cruise can get you across the Atlantic one-way**, provided the operator agrees to your booking without a return flight.

The clearest options I found are:

- **Jamaica, entirely by sea:** Phoenix Reisen’s *Amadea* sails from **Bremerhaven, Germany, on 22 October 2027**, finishing in **Montego Bay on 17 November**—a 26-night journey. You could then travel overland to Kingston. The advertised fare starts at **€3,699 per person**, but includes a return flight to Frankfurt: ask Phoenix for a passage-only booking, or confirmation that you can stay in Jamaica and leave that flight unused. [Official itinerary and package details](https://www.phoenixreisen.com/von-bremerhaven-bis-jamaika.html).

- **Trinidad, avoiding a long-haul flight:** P&O’s *Britannia* sails from **Southampton on 30 October 2026 to Bridgetown, Barbados, on 13 November**, taking 14 nights. Caribbean Airlines sells flights from Barbados to Port of Spain, so this would leave only a regional flight. Confirm a cruise-only arrangement with P&O before booking. [P&O itinerary](https://www.pocruises.com/find-a-cruise/B626/B626), [Caribbean Airlines route](https://flights.caribbean-airlines.com/en/flights-from-bridgetown-to-port-of-spain).

**For an entirely flight-free journey to Trinidad, I haven’t found a confirmed bookable crossing ending in Port of Spain.** A cruise calling there would need explicit confirmation that you may finish your journey at that stop. Trinidad’s regular inter-island ferry connects it with Tobago; it doesn’t provide a connection from Europe or Barbados. [Trinidad and Tobago ferry operator](https://www.ttitferry.com/sidebar/).

Cargo-ship passage is another possibility to investigate, but I couldn’t verify a current passenger service from Europe to either destination. I would treat old freighter itineraries as leads, not confirmed transport.

Your intended month and year would help narrow this down considerably: these crossings depend on particular sailings rather than a regular ferry timetable.