How did you enter a race before the internet?

Online race registration wasn't common until ~20 years after the founding of the modern internet, so I'm not sure why "before the internet" is your time cutoff. The internet has existed since 1983. I was still mailing paper registration forms with checks in 2000.

In the UK at least, a lot were advertised in Athletics Weekly or Runner's World. If it was a track open meeting mostly you could turn up, queue and enter on the day (usually up to about an hour before the heat was scheduled).

For road races you typically needed to enter in advance. So you would send them, via the post, a cheque for the race fee along with a form that you'd filled in with your details and then they would send you your race number, a map of the course and other information before the race day.

I also remember waiting to have race results mailed out to me. Often took a few days. You'd know roughly where you finished but not full results for a long time, or you'd wait until the weekday that Athletics Weekly came out on.

I fondly remember that part of a runner's routine in the 80s and 90s was to swing by the local running shops on the weekends to pick up race flyers or to see if any new ones were available. Often times, you would meet other local athletes doing this finding training partners and new friends. As others stated, races were relatively inexpensive, entries paid via check, and you sent the entry via postal mail. Back then, the local newspaper would print the results in the sports section a day or two after the race. You were bougie if you owned a Timex Ironman watch that could hold 40 splits! Races were often a surprise. Unless the event had been held for many years prior, you often didn't know what the course was like as there wasn't room on the flyer to print a map or course description. "Flat and fast!" or "Challenging with rolling hills" did not have standardized definitions.

Road racing was a huge deal back then. I am a bit baffled why it isn't today as the technology has made it much easier to sign up, get your results, study the course, etc.

"Before the internet" means around 2000 for most people.
And funny enough people are still mailing checks in 2024.

In the early '80's I was trying to break 4 minutes for the mile. My country is metric, so I got a copy of Track and Field News from the library and wrote out the names of contract people for various meets in America. I then wrote letters to about 8 of them and managed to schedule several mile races over a 2 month period. I had a 1977 Ford Pinto (the one that exploded if hit from behind), a tent and some supplies. I'd drive to a meet and then sleep either in the tent or the car (it rained a lot). I ran 4:06 twice, but no faster. I suppose today if I were 25 again, I'd do the same thing except over the internet.

find a race flyer in the local running store, gym, or a magazine. I'd have my dad write a check, and I'd reimburse him cash. Mail the check and entry form. Eventually I got my own checks. I also did a lot of triathlons in 80s the same way. Cash on race day was also a good option if the weather was a factor.

I think every race I ran in those years had a bulletin board around the finish line and posted results sheets on it. You had to hang around for a little while for them to get typed up and posted but not for very long.

I had a Pinto for a while, a '72 I think. I'm impressed you found a way to sleep in it.