Si5 Spy Missions Chelmsford is an exciting indoor adventure centre located in Duke Street, Chelmsford, where children (and adults) become secret agents for the day. It offers immersive, story-based escape-style missions that combine puzzles, teamwork, and physical challenges in a thrilling secret-agent setting.

The experience includes climbing through laser mazes, cracking safes, venturing through vents, and solving computer-based puzzles to complete daring spy missions. Each session is guided by a personal mission leader, and the difficulty automatically adjusts based on players’ ages and abilities — making it suitable for kids, teens, and adults. For older visitors (14+), the Operation Covert Sword mission adds a more complex challenge involving stopping a rogue agent before a missile strike on London.

Pricing is £17.50 per person (up to 8 players), £16.00 each for 9 or more players (including food), or £14.00 for the mission only (2–24 players). Birthday parties are a highlight, with packages including a full spy adventure, food, and dedicated guides.

Overall, Si5 Spy Missions Chelmsford is a must-visit for families and groups seeking indoor adventure and teamwork fun. With clever puzzles, cinematic storylines, and great value pricing, it’s one of the best interactive experiences in Chelmsford.

• Agent Malice has seized the ship and is heading for London. Only your children can stop him. Steal the stealth boat and catch up with Steadfast, climb through lasers and vent shafts, crack computers and safes on a high speed adventure to save the day. Our kids escape room features brilliant physical and mental puzzles set in a stunning storyline with interactive computers and your own dedicated guide. The computers adjust the difficulty of the tasks and puzzles in the mission according to the age and ability of the children. Young kids will also receive more hints and help from their guide, whilst older kids will be challenged with more complex tasks.
• Our puzzles are designed so you cannot remember the solutions, we have an average of 6 repeat visits for each child and they enjoy it every time. Spy Missions is the perfect party venue, we supply lovely cooked food in our bright friendly café and you get peace and quiet for an hour while we whisk your children off on their adventure through the Battle Cruiser before coming back out to find their table set up with drinks and spy packs and food on its way. If you're looking for an indoor activity or something to do with the kids when it's raining, Spy Missions is the perfect solution!
• Operation - Covert Sword (14+): SpyMissions is an incredible mix of physical and mental challenges, set into an exciting storyline! Crack safes, climb through lasers and seize control of the ship to get to the missile in time and abort the launch! Nigel Palmer, once an SI5 operative, has gone rogue. Using inside information, he and a group of mercenaries calling themselves The Plague have seized control of UNS Steadfast, an Orion Class Battle Cruiser armed with 6 Nuclear missiles. Palmer, using the pseudonym Agent Malice, claims he has the missile launch codes and intends to attack London starting World War 3. Your mission is to covertly board the ship and use every possible avenue to slow her down and stop her getting within range of her target, disable Palmer's men and lock down the ships systems. You need to buy enough time to get to her missile bay and stop the launch.