21-Night Cruise on OosterdamCroatia, Greece & Istanbul Collectors' Voyage - Weather

Departing Trieste, Italy on September 23, 2026, the Holland America Line (HAL) ship Oosterdam runs this 21-night Croatia, Greece & Istanbul Collectors' Voyage sailing. It's a classic Mediterranean cruise. Travelers sailing in September can generally expect mild, changeable weather that can turn cool and wet. Ports of call include Trieste, Italy, Rijeka, Croatia, Split, Croatia, with 14 more along the way. Scroll the daily outlook below to pack smart for every port of call.

1. Day 1 — Wednesday, Sep 23, 2026 — Trieste, Italy

   Trieste, Italy is a scheduled port of call on day 1 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 72°F.

2. Day 2 — Thursday, Sep 24, 2026 — Rijeka, Croatia

   Rijeka, Croatia is a scheduled port of call on day 2 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 70°F.

3. Day 3 — Friday, Sep 25, 2026 — Split, Croatia

   Split, Croatia is a scheduled port of call on day 3 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 73°F.

4. Day 4 — Saturday, Sep 26, 2026 — At Sea

   Day 4 of 22 is a day at sea aboard Oosterdam, cruising between ports on the Croatia, Greece & Istanbul Collectors' Voyage itinerary.

5. Day 5 — Sunday, Sep 27, 2026 — Santorini, Greece

   Santorini, Greece is a scheduled port of call on day 5 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: clear with highs near 74°F.

6. Day 6 — Monday, Sep 28, 2026 — Bodrum, Turkey

   Bodrum, Turkey is a scheduled port of call on day 6 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: clear with highs near 76°F.

7. Day 7 — Tuesday, Sep 29, 2026 — Kusadasi, Turkey

   Kusadasi, Turkey is a scheduled port of call on day 7 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: clear with highs near 83°F.

8. Day 8 — Wednesday, Sep 30, 2026 — Istanbul, Turkey

   Istanbul, Turkey is a scheduled port of call on day 8 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 74°F.

9. Day 9 — Thursday, Oct 1, 2026 — Istanbul, Turkey

   Istanbul, Turkey is a scheduled port of call on day 9 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 70°F.

10. Day 10 — Friday, Oct 2, 2026 — At Sea

    Day 10 of 22 is a day at sea aboard Oosterdam, cruising between ports on the Croatia, Greece & Istanbul Collectors' Voyage itinerary.

11. Day 11 — Saturday, Oct 3, 2026 — Piraeus, Greece

    Piraeus, Greece is a scheduled port of call on day 11 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 82°F.

12. Day 12 — Sunday, Oct 4, 2026 — Nafplion, Greece

    Nafplion, Greece is a scheduled port of call on day 12 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 72°F.

13. Day 13 — Monday, Oct 5, 2026 — At Sea

    Day 13 of 22 is a day at sea aboard Oosterdam, cruising between ports on the Croatia, Greece & Istanbul Collectors' Voyage itinerary.

14. Day 14 — Tuesday, Oct 6, 2026 — Istanbul, Turkey

    Istanbul, Turkey is a scheduled port of call on day 14 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 70°F.

15. Day 15 — Wednesday, Oct 7, 2026 — Istanbul, Turkey

    Istanbul, Turkey is a scheduled port of call on day 15 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam. Expected weather: partially cloudy with highs near 70°F.

16. Day 16 — Thursday, Oct 8, 2026 — At Sea

    Day 16 of 22 is a day at sea aboard Oosterdam, cruising between ports on the Croatia, Greece & Istanbul Collectors' Voyage itinerary.

17. Day 17 — Friday, Oct 9, 2026 — Kusadasi, Turkey

    Kusadasi, Turkey is a scheduled port of call on day 17 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam.

18. Day 18 — Saturday, Oct 10, 2026 — Santorini, Greece

    Santorini, Greece is a scheduled port of call on day 18 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam.

19. Day 19 — Sunday, Oct 11, 2026 — Rhodes, Greece

    Rhodes, Greece is a scheduled port of call on day 19 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam.

20. Day 20 — Monday, Oct 12, 2026 — At Sea

    Day 20 of 22 is a day at sea aboard Oosterdam, cruising between ports on the Croatia, Greece & Istanbul Collectors' Voyage itinerary.

21. Day 21 — Tuesday, Oct 13, 2026 — Chania, Crete

    Chania, Crete is a scheduled port of call on day 21 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam.

22. Day 22 — Wednesday, Oct 14, 2026 — Piraeus, Greece

    Piraeus, Greece is a scheduled port of call on day 22 of the 21-night Croatia, Greece & Istanbul Collectors' Voyage cruise on Oosterdam.