It’s possible to train for a triathlon without using a GPS watch, but why would you? The right watch will let you track your laps and pace in an indoor pool, and distance and pace on outdoor swims, bikes, and runs. I use the Garmin Forerunner 920, which can be had for about $300. The killer app on this model is bluetooth connectivity to my phone which uploads my workouts automatically once I’m finished, and my phone sends them alone to my TrainingPeaks website so my coach can see my performance. Easy peasy. One small issue that I do have with my Garmin watch is it drastically overestimates my caloric burn on long bike rides, which is an issue that many other athletes have noted. There are several online resources which estimate caloric expenditure, and my Garmin’s numbers are typically 50% to 100% over their calculations. While it’s great to look down at the end of a 100 mile bike ride and see a notification that I just burned 10,000 calories, I know the actual number is perhaps half of that.
You will need to get a tri kit at some point before your race, but you do not need to train in it. A tri kit is a one or two piece suit which is suitable to wear on the swim, bike, and run portions of a triathlon race. These kits will have less padding in the seat than dedicated bike shorts, but will still be adequate for protection during your race ride. It is technically possible, but not advised, to change clothes during a race. I use a one-piece singlet from a brand called Fusion, which is possibly the most comfortable thing I’ve ever worn. One-piece versus two-piece kits are a matter of personal preference; one-piece suits look like wrestling singlets and have less seams and lines to potentially chafe your skin, but a two-piece setup makes it easier to go to the bathroom. On my first half Ironman in my Fusion suit, I threw on a jacket after the swim because the morning was still chilly. While on the bike section, I realized that in order to pee, I now had to take off my bike helmet and jacket before I could unzip the front zipper of my suit and pull it down. After that race, if I am worried about being chilly on the bike, I will put on a long-sleeve shirt under my tri kit, so I can operate the zipper and put the suit down without taking my helmet off. My kit is sleeveless, which is cooler but also increases the potential for sunburned shoulders during a long race.
Many triathletes are obsessed with the latest and greatest technology, which means great deals are commonly available on last year’s equipment. Look on Craigslist, eBay, or Facebook Marketplace to find gently used equipment for a bargain price. A two-year-old GPS watch will track your run splits just as accurately as this year’s model.