Hi Jackie, Thank you for your enquiry. Unlike the harness straps, the buckle strap on the Britax Boulevard Click Tight is unfortunately not adjustable. However, as this is quite a common occurance with US Standard seats, some manufacturers can suply extended buckle starps for their seats. We would recommend contacting your nearest Baby On The Move store who can in turn contact the manufacturer on your behalf to ascertain if this is possible for you. If you follow the link https://www.babyonthemove.co.nz/store-locations// this will take you to our on-line store finder where you can find contact details for your nearest Baby On The Move store. We hope this has helped with your query.