SubDL has 46 subtitles for Frontier(s) AKA Frontiers (Frontière(s)) across 18 languages. New subtitles are added as the community uploads them.
Frontier(s) AKA Frontiers (Frontière(s)) subtitles are available in English, Swedish, Indonesian, Arabic, Danish and more — 18 languages in total.
Open the language you want, pick the release that matches your video file, and click the download button. The file is a free .srt and no account is required.