It takes place on Tuesday July 19 from 10.30am to 3.30pm at the reserve’s pavilion.
Free activities on offer include bird box building, bug bingo, pebble painting, wildlife viewing with scopes, medallion making and yoga on the beach.
Storytelling sessions will take place at 11:00am and 2:00pm, and beach Olympics will get underway at 1:00pm. There will also be music throughout the day from the Ferryport Fiddlers.
Butterfly Conservation will be leading guided butterfly walks for visitors to learn about the butterflies of Tentsmuir and take part in a survey for the elusive grayling butterfly.
Marijke Leith, NatureScot’s reserve manager, said: “Tentsmuir is a really special place and our open day is a great opportunity to get to know the reserve and its wildlife.
“From beach yoga to wildlife watching and expert butterfly walks, there’s something for everyone to enjoy.
“There’s no need to book, people can just turn up and take part in as many of our fantastic free activities as they like.”
Visitors can also park at the Kinshaldy car park - c- ost £2 in coins) and a free shuttle bus will be running from the car park to the reserve throughout the day.
For those who prefer to walk or cycle, the pavilion is 1.5miles from Kinshaldy car park.
For more information on the event, please go to https://www.facebook.com/tentsmuirNNR/