Timetables can be found in english in Kotka region (Kotka, Hamina, Pyhtää) journey planner kotka.digitransit.fi (languages fin, swe, eng)
Timetables of Pyhtää also here in finnish (pdf):
Pyhtää_2022-2023 timetables (in finnish, pdf)
Look changes to long distance buses
Long distance buses
Service Line (Roones) -Pyhtää kk – (Purola) – Siltakylä