Twitter has made searching for an account’s first tweet pretty simple via this link.
So, here are some first tweets from notable Olympian accounts, in chronological order:
https://twitter.com/NBCOlympics/statuses/823535421
https://twitter.com/shaun_white/statuses/971546309
https://twitter.com/taylorphinney/statuses/975359561
https://twitter.com/usatf/statuses/1137069052
https://twitter.com/Carl_Lewis/statuses/1147444655
https://twitter.com/2010Tweets/statuses/1205330476
https://twitter.com/chadhedrick/statuses/1453412026
https://twitter.com/AtoBoldon/statuses/1573480595
https://twitter.com/RyanLochte/statuses/1616766325
https://twitter.com/USFigureSkating/statuses/1630695180
https://twitter.com/JohnnyGWeir/statuses/1792606608
https://twitter.com/USAGym/statuses/1960984662
https://twitter.com/usainbolt/statuses/2151633289
https://twitter.com/CharlieaWhite/statuses/2287651357
https://twitter.com/lindseyvonn/statuses/2357572747
https://twitter.com/lolojones/statuses/3294866864
https://twitter.com/Meryl_Davis/statuses/4899774305
https://twitter.com/donovanbailey/statuses/7374717325
https://twitter.com/MJGold/statuses/7854715605
https://twitter.com/Olympic/statuses/12957794855
https://twitter.com/AshtonJEaton/statuses/22418297929
https://twitter.com/MichaelPhelps/statuses/13701532704837633
https://twitter.com/sagekotsenburg/statuses/24525438952939521
https://twitter.com/hopesolo/statuses/76027859310886913
https://twitter.com/marylouretton/statuses/86142436350509056
https://twitter.com/FranklinMissy/statuses/109091749967839232
https://twitter.com/JasonLezak/statuses/226033775723831298
https://twitter.com/katieledecky/statuses/233605484505088000
https://twitter.com/bonnieblair/statuses/427476499164188672
