According to the search results, the answer to "what days is MAFS on 2023?" depends on which version of the show you are referring to.
- Married at First Sight UK 2023 started on Monday, September 18 at 9pm on E4. Episodes continue to air on Monday, Tuesday, Wednesday, and Thursday, and the series is set to be the longest running yet with 36 episodes.
- Married at First Sight US season 17 premiered on Wednesday, October 18, 2023, at 8 p.m. ET on Lifetime.
- Married at First Sight Australia season 10 premiered in 2023, but the search results did not provide information on the specific days it airs.