You don't have to remember. The answer is usually on your phone already. Six places to look.
If location history was on, Google Maps kept every park day. Open Timeline, pick a year or month and you see where you were per day, park name included.
Since 2024 your timeline lives on your phone. Look in the Google Maps app under your profile picture, Your timeline.
Open Google Maps TimelineSearch Google Photos or Apple Photos for the park name or the town. The app often recognises the park already. If not, use the map view. The photo date is your visit date.
Old photos in WhatsApp groups or on an external drive carry a date too, in the file details.
Search your inbox for the park name. E-tickets, parking reservations, hotel confirmations and newsletters you signed up for on the spot all give away the day.
Also search for the name of the park hotel or holiday village.
A card payment at the gate, the gift shop or a restaurant shows up on the day itself. Search your banking app for the park name or the town.
Most banking apps go back years. Filter on a large summer expense.
Instagram, Facebook and Snapchat keep your posts and stories with a date. Check your archive, or use On this day and Memories.
A tag or check-in by someone else counts too.
Someone in the group usually remembers, or has the photos. Tag them on your visit and they get asked whether they want to log it too.
Two half memories often make one whole date.
You don't have to pick an exact day. A year alone, or a year and a month, is enough. Ridden works with that without inventing a date. When in doubt, a year with a note beats nothing.
Had a pass or subscription? Log that period on the park and your history shows from when to when a park was yours, even if you never logged every single visit.