We visited Flint Castle in the town of Flint, in Flintshire in North Wales during August this year (2021). It took a bit of finding as the signage was not great - but we were really impressed when we got there. Although a ruin, its massive, and overlooks the River Dee Estuary towards England (the Wirral).
Although a ruin, its safe to enter, and is maintained by CADW. Entry is free, as is the parking ! If has four of these large towers at each corner, which encloses quite a substantial area - we were quite blown away by the size in general. It has the sea on 2 sides, and then what was a moat on the other two. It must have been a heck of a place in its day.
You can walk right around the outside as well, although you may have to watch the tides, and it can be a bit wet under foot in places (on the seaward side). The views out to sea, over the river Dee are quite impressive, and here you can see that the tide is right out, revealing the mud flats, with the Wirral in the distance.
There were some information boards around, and some with sound that you could play and listen to, providing detail on the history. Kids would love it as there is lots of space to run around, and walls, etc to climb on. There is also quite a large grassed area out the front of the castle, which would be good for picnics, games, etc.
It wasn't very busy, so there was no crowds to fight through, and no waiting in line for anything - I guess its not so well advertised - but I dont know why, because we loved it - so much so that we went back again during the same week to walk around it further.
The pic above shows the remains of the North West Tower.
The picture above shows the main wall from the town/land side of the castle. The picture below is taken from the sea side of the castle, which is easily accessible when the tide is out.
The following helps to provide scale to the enclosed inner area.
The pic below shows the entrance gate (from the inside) and some of the 'rooms' on the landward wall which you can enter/look into.
All in all, we really enjoyed it and would thoroughly recommend it - and we will definitely visit it again if/when we are back in the area.
If you want to know more, including the location - then check out the Flint Castle link on the CADW website.