Skip to main content
Cart 0
Your Bag

Monterey® 5iST FixSafe


or 3 interest-free payments of £100.00. Learn More

Enjoy worry-free buying and perks with the Diono Difference

Receive perks when you shop on

Additional 2-Year Warranty

Receive an additional 2-year warranty on all car seats and strollers purchased from

Free Shipping on orders over $400*

Diono proudly offers free shipping on orders over $400

Unlock exclusive offers & discounts

Unlock exclusive news, offers and discounts on all products.

1-2-1 Virtual Car Seat Fitting

Book a 1-2-1 virtual car seat fitting with a member of our car seat safety team.

Monterey® 5iST FixSafe

Designed for ultimate portability, Monterey® 5iST FixSafe™ i-Size transforms in seconds from a compact fold to a full-size high back booster seat, without compromising safety or comfort. At 25% smaller than the average booster seat, Monterey® 5iST FixSafe™ i-Size folds down into a compact and convenient size and features an integrated carry handle and carry straps. So with Monterey® 5iST FixSafe™ i-Size you can always take safety with you for the joy of the journey. Suitable from 100 - 150 cm / Group 2/3 (approx. from 4 to 12 years or 15 - 36kg.).


  • EXPANDS IN HEIGHT AND WIDTH - One-hand automatic height and width adjustment provides a custom fit for optimum comfort and safety.
  • COMPACT FOLD TO FULL SIZE BOOSTER IN SECONDS - 25% smaller than the average booster seat without compromising safety or comfort.
  • FIXSAFE™ ISOFIX CONNECTORS - Easy install with FixSafe™ isofix connectors for a safe and secure installation every time.
  • 8 YEARS ONE BOOSTER - 12 headrest positions and expandable sides to grow with your child from 100 - 150 cm (Group 2/3 15 - 36kg approx. 4 - 12 years) Machine Washable fabric and convenient cup holder ensure your child's booster seat stays clean and comfortable.
  • SAFE+® ENGINEERING - Includes 9 layers of Safe+® side impact protection (including Side Impact Management Pod) and rigorous crash testing to meet and exceed the latest European ECE R129 standard.
  • TAKE SAFETY WITH YOU - Features integrated carry handle and carry straps for 3 ways to carry.

Product Specs

  • Minimum User Weight: 15 kg
  • Maximum User Weight: 36 kg
  • Product Height: 63 cm
  • Product Width: 45.5 cm
  • Product Depth: 38 cm
  • Seat Weight: 8.5 kg
  • Maximum User Height: 150 cm
  • Number of Head Support Positions: 12
  • Product Height - Folded: 59.5 cm
  • Product Width - Folded: 45.5 cm
  • Product Depth - Folded: 19 cm

Care & Maintenance

Covers: Machine wash cold, line dry. Shell and Components: Spot clean

Warranty Information

12 months