You can replace a Timex Ironman battery yourself with a screwdriver, or take it to a jeweler or watch repair shop

Most Timex Ironman watches use a standard coin-cell battery — usually CR2032, CR2016, or SR927W depending on the model — that you can swap out at home in under five minutes. The watch case opens from the back with a small Phillips or flathead screwdriver. If you are not comfortable opening the watch yourself, a jeweler or Timex service center will do it for $10 to $25, usually while you wait.

The battery itself costs $3 to $8 at a drugstore, supermarket, or online. Timex does not sell batteries separately; you buy the generic type that matches your model number. The hardest part is usually getting the case back off without scratching the watch, not the battery swap itself.

Key Takeaways

  • Timex Ironman watches use a coin-cell battery (CR2032, CR2016, or SR927W) that you can identify by checking your watch model number in the manual or on Timex's website.
  • You need only a small Phillips or flathead screwdriver to open the case back and remove the old battery; the whole job takes five minutes.
  • A new battery costs $3 to $8 and is available at any drugstore, supermarket, or online retailer.
  • If you do not want to open the watch yourself, a jeweler or Timex service center will replace it for $10 to $25.

Find your watch model and the correct battery type

The battery type varies by Timex Ironman model. Look at the back of your watch case for a model number — it usually starts with T5 or T5K. Write down the full number. Then go to Timex.com, search for your model, and open the product page or manual. The manual will list the battery type in the specifications section.

If you cannot find the manual online, you can also take a photo of the model number to a jeweler and ask them to identify the battery. Most will tell you for free. The three most common Ironman batteries are CR2032 (the largest), CR2016 (slightly smaller), and SR927W (a silver-oxide type used in some digital models). Do not guess — using the wrong battery can damage the watch or cause it to malfunction.

Buy the correct battery and gather your tools

Once you know the battery type, buy it at a drugstore, supermarket, pharmacy, or online. Walgreens, CVS, Walmart, and Target all stock common coin-cell batteries in their watch or electronics sections. Amazon and eBay sell them in bulk if you want extras. A single battery costs $3 to $8; a pack of five costs $8 to $15.

You will also need a small screwdriver — either Phillips head or flathead, depending on your watch model. Most Ironman watches use a Phillips head. If you do not have one, a jeweler's screwdriver set costs $5 to $10 at a hardware store or online. A regular household screwdriver is often too large and will slip or damage the screw.

Open the case back and remove the old battery

Lay the watch face-down on a clean, flat surface. Locate the small screw (or screws) on the case back. Most Ironman watches have one central screw; some have two or three around the edge. Turn the screw counterclockwise slowly and carefully. The screw is small and straightforward to lose, so work over a table or tray where it cannot roll away.

Once the screw is out, gently pry the case back off using the edge of the screwdriver or a plastic spoon. Do not use a metal tool directly on the case back — it will scratch. The case back should come off with light pressure. Inside, you will see the battery sitting in a small metal holder or clip. Note which side is facing up (the + or – symbol should be visible on one side). Gently lift or pry the battery out with the screwdriver tip or a plastic tool.

Insert the new battery and close the watch

Take the new battery and orient it the same way the old one was facing — usually with the + side up. Slide it into the metal holder or clip until it sits flat and snug. Do not force it; it should fit easily. If the battery does not sit flat, you may have the wrong type — stop and double-check the model number.

Once the battery is in place, line up the case back with the watch body and press it down gently until it clicks or sits flush. Then insert the screw and turn it clockwise until it is snug. Do not over-tighten — you only need enough pressure to hold the case closed. The watch should now power on. If it does not, the battery may be dead (rare for a new one) or you may have inserted it upside down. Open the case again and flip the battery.

What to do if you cannot open the watch yourself

If the screw is stuck, stripped, or you do not feel confident opening the watch, take it to a jeweler, watch repair shop, or Timex service center. Most jewelers will replace the battery while you wait for $10 to $25. Timex service centers charge a similar amount and usually take one to two weeks. Call ahead to confirm they have your battery type in stock.

Some Timex retailers (like Dick's Sporting Goods or Best Buy) also offer battery replacement, though not all locations do. Check their website or call first. If your watch is still under warranty, Timex may replace the battery for free, though the warranty typically covers defects, not normal battery wear.

How to know if the battery is truly dead

A dead Ironman battery usually means the display goes blank, the watch stops keeping time, or the buttons stop responding. If the watch is still showing time but the display is dim or flickering, the battery may be low but not completely dead — a new battery will fix this. If the watch does nothing at all when you press buttons, the battery is dead.

Before you assume the battery is dead, make sure you inserted it correctly (+ side up) and that the case back is fully closed and screwed in tight. A loose case back can interrupt the circuit and make the watch appear dead even with a good battery. If the watch still does not work after you have checked these things, the battery is likely dead or the watch has an internal problem that a jeweler should look at.

Frequently Asked Questions

Can I use a different battery type if I cannot find the exact one?

No. Using the wrong battery type can damage the watch circuit or cause it to malfunction. CR2032 and CR2016 look similar but have different thicknesses and voltages. If you cannot find the exact type, order it online or ask a jeweler to order it for you. It usually arrives within a few days.

How long does a Timex Ironman battery last?

Most Timex Ironman batteries last two to five years depending on how often you use the watch and which features you use (backlighting and alarms drain the battery faster). There is no way to predict exactly when it will die, so replace it when the display goes blank or the watch stops keeping time.

Will opening the watch void the warranty?

Opening the watch yourself may void the warranty if your watch is still under the manufacturer's warranty period. Check your warranty paperwork or Timex.com to see what is covered. If the watch is out of warranty, opening it yourself will not matter. If it is still under warranty, a jeweler or Timex service center is the safer choice.

What if I lose the screw when I open the watch?

If you lose the screw, a jeweler can usually replace it with a matching one for $2 to $5. You can also order replacement screws online for Timex watches, though you need to know the exact size. Do not close the watch without a screw — the case back will not stay sealed and water or dust can get inside.

Is the Timex Ironman water-resistant after I replace the battery?

Yes, as long as you close the case back properly and the screw is tight. The case back seal is what keeps water out, not the battery itself. If you are worried about water resistance, have a jeweler test it after the replacement — they can use a pressure tester to confirm the seal is good.