when did the astros cheat

The Houston Astros’ sign‑stealing scheme is most closely associated with the 2017 MLB season, including the postseason, with some activity continuing into early 2018 before it was stopped.

Core timeline

• The electronic sign‑stealing system was developed and outlined internally around September 2016 , when staff presented “Codebreaker,” a plan to decode opposing catchers’ signs using video.

• The system was implemented during the 2017 regular season , using a center‑field camera feeding into a monitor near the dugout; players then banged on a trash can to signal upcoming off‑speed pitches.

• MLB’s investigation later concluded the Astros illegally stole signs during the 2017 regular season and postseason , the year they won the World Series.

How long did it last?

• MLB found that the main trash‑can based scheme continued into the 2018 regular season before players stopped using it, and there was no evidence of the same system in 2019.

• There were also earlier, less formal efforts to use video for sign stealing discussed in 2016 , but 2017 is considered the peak and the season most fans mean when they ask “when did the Astros cheat.”

When it became public and punished

• On November 12, 2019 , The Athletic published the whistleblower story (with ex‑Astro Mike Fiers on the record), which blew the scandal open and triggered MLB’s full investigation.

• On January 13, 2020 , MLB announced its findings and punishments: one‑year suspensions for GM Jeff Luhnow and manager A.J. Hinch, a $5 million fine, and loss of first‑ and second‑round draft picks in 2020 and 2021; the Astros then fired Luhnow and Hinch the same day.

Quick “forum style” recap

In forum threads and fan debates, “when did the Astros cheat?” usually means:
they ran a camera‑based sign‑stealing operation mainly in 2017 , used some version into early 2018 , and got exposed and punished between late 2019 and early 2020.

TL;DR: The Astros’ cheating is tied primarily to the 2017 season (including playoffs) , with remnants into early 2018 , and it came to light in late 2019 with punishments in January 2020.

Information gathered from public forums or data available on the internet and portrayed here.