"Miaj gepatroj volas vojaĝi eksterlanden ĉiujare."

Translation: My parents want to travel abroad every year.

[babelpescado]

"my parents want to travel internationally every year" <--is that ok?

[mizinamo]

No, I don't think so, though that might work for "eksterlande" without the -n.

"Travel internationally" could mean for a French couple to travel from Thailand to Australia.

But eksterlanden with -n has direction, "to a foreign country", implying that their trip starts in their local country.

[zerozeroone]

But eksterlanden with -n has direction, "to a foreign country", implying that their trip starts in their local country.

Does it?

For eksterlando, votaro.net shows:
Ĉio, kio estas ekster la koncerna lando

If a trip starts in Thailand, that's the country in question, no matter where the people taking the trip are from.

[farl_]

Ili evidente ne scias kiom tio kostas...

[JohnWathen]

Aŭ eble ili estas Esperantistoj.