I plan to go to Vaxholm from Stockholm, spent few minutes or an hour there, then take another ferry from Vaxholm to another island, stop in the second island, etc. Do i need to pay a fare everytime I board the ferry? Thanks
Yes. Unless you have a period card for the ferry company, you pay for each journey.
Waxholmsbolaget has a 5-day period but it is 595 SEK. I doubt your single tickets will add up to this.
https://waxholmsbolaget.se/visitor-information/tickets/fares-tickets
But I'd suggest you make a rough plan to see if the 5 day ticket makes sense. If you plan to do a lot of travel in one day the 5 day ticket might be a good idea.
Thanks Laura and Badger. Good info and advise.