For older children, you can learn about the huge searchlights at Coalhouse Fort, assemble a torch and learn to use Morse code!
All activities must be booked in advance and cost Â?5 per child.
Portfolio Holder for Neighbourhoods, Cllr Sue MacPherson said: "Coalhouse Fort is one of Thurrock's gems being recently re-awarded the coveted Green Flag award.
"Whilst the weather remains a little grey and damp, these events are a great way to get the whole family outdoors but undercover.
"With a free car park, beautiful riverside location and public amenities like toilets and disabled toilets â?? there is no reason not to go outdoors and get involved this summer."
For more information and to book tickets, go to thurrock.gov.uk/events