The event was held on the beach at Brancaster, which the trust owns, on Saturday.
Alex Green, from the trust, said: “It went really, really well. We gave away over 800 free sticks of rock and had lots and lots of people taking part.”
Brancaster was one of 26 locations around the country where picnics were held on Saturday to celebrate the 50th anniversary of the Neptune Coastline Campaign.
The campaign has helped to acquire and look after 775 miles of coastline, including a 62 mile stretch of the Norfolk coast.
And, with a hot, sunny day making a trip to the coast all the more appealing, visitors were able to enjoy a range of activities, including sandcastle building with free buckets and spades, cricket, rounders and swingball. There were also giant deckchairs for people to relax and soak up the sun.
Equipment was provided by the trust and Miss Green said the day was an important way to help raise public awareness of the trust’s ownership of the site.
She said: “We probably will do something like that again next year.”