Yep as above, but most smart phones also have the capability nowadays or if you wanted to spend money, Garmin sell a GTU10 tracker for around £180 from Currys
Don't stress about a fast time, enjoy the first half while you can remember it. Yes you wil run an extra half mile high fiving the kids, but they deserve it for supporting us. and whatever you do dont let you family take you for a celebratory drink afterwards, just get back to your hotel asap and start recovering..