How do you change the year on the Timex marathon? Right now it says 2023 not 2018 and I cannot find which button decreases the year. I did find which on increases.

https://www.timex.com/watch-manuals.html
Search for Marathon - its there.

how do i decrease the year?

To set time and date:
1) With time and date showing,
press SET and hold for 2 seconds.
2) Seconds flash. Press START/STOP to set seconds
to zero.
3) Press MODE
.
Hour flashes.
Press START/STOP
to change hour, including AM (no symbol) and PM.
4) Press MODE
.
Minutes flash.
Press START/STOP to change
minutes; hold button to scan values.
5) Press MODE. Year flashes.
Press START/STOP to change year.
6) Press MODE
.
Month flashes.
Press START/STOP
to change month.
7) Press MODE
.
Date flashes.
Press START/STOP
to change date.
8) Press SET
, at any step, to exit and save settings.
With time and date showing, press SET
to switch between 12- or 24- hour time format.
Date (day of month) appears in upper part of display in Time
mode. Press and hold START/STOP
to see month, date, and year in large digits

Or go to:
http://assets.timex.com/user_guides/Marathon/W292-Marathon-AllLanguages.pdf

try this link below
http://assets.timex.com/manuals/?timexBrand=core

Lily, Check the attached links Timex manuals,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
How to change military time to AM PM time on Women Timex 1440 Sports Watch
http://assets.timex.com/user_guides/W15_M774/W15_M774_NA_EN.pdf
http://www.timex.com/info/watch-manuals

Pam, Check the attached links,instruction and manuals, 1st link is Timex where you can request the manual. Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."
http://timex.ca/ https://www.timex.com/sites/default/files/W116_M555_NA_EN_4.pdf Timex Marathon Manual
http://fitness.manualsonline.com/manuals/mfg/timex/timex_watch_product_list.html

I'm guessing that your watch is described here
http://www.walmart.com/ip/Marathon-by-Timex-Digital-Mid-Size-Black-and-Silver-Tone-Watch/38229915
(at the bottom it says model = T5K805, name is marathon)
[also on Amazon - http://www.amazon.com/Timex-Womens-Marathon-Sports-Digital/dp/B00R4XTAJ8/ref=sr_1_3?s=apparel&ie=UTF8&qid=1421449802&sr=1-3&keywords=t5k805&pebp=1421449828860&peasin=B00R4XTAJ8)

Then.look down the list for marathon in this http://www.timex.co.uk/info/product-manuals-downloads
and choose the one of the three you want. The non GPS one is very short and not really what I'd call a manual. I hope this is what you need. Otherwise contact Timex

16.January.2015

Timex Product Manuals Downloads

1. Press Mode- and set it on the alarm.
2. When you are here, press the start/stop button and the little alarm signal will change. If it is dark, the alarm is on. If you keep pressing the stop/start button the darkness will go away, meaning the alarm is now off.

For setting instructions on all Timex watches go to Timex.com and download your manual.

Holding down the mode button will put you in set mode. You can then cycle through the fields and set the watch using the srt and rst buttons.