You can replace a Timex Ironman battery yourself in about five minutes with basic tools

Timex Ironman watches use a standard coin-cell battery—usually a CR2032, CR2016, or SR626SW depending on your model year—that you can buy at any drugstore or hardware store for two to five dollars. The back of the watch opens with a coin or small screwdriver, the old battery slides out, and a new one slides in. You do not need to send the watch away or visit a jeweler unless the case is sealed or you are uncomfortable opening it yourself.

The entire job takes longer to read about than to do. This guide walks you through the steps, what tools you actually need, and when to stop and call someone else.

Key Takeaways

  • Timex Ironman watches almost always have a removable case back held by a coin slot or small Phillips screw, not a sealed design.
  • The battery type is printed on the back of the watch case or in your manual—check before you buy a replacement.
  • You need only a coin, a small flathead screwdriver, or a watch case opener tool; jewelers sell openers for five to ten dollars if you want a dedicated tool.
  • Once the case back is off, the battery sits in a metal holder and lifts straight out; the new battery goes in the same way with the positive side facing up.
  • If the case back is stuck, sealed, or stripped, stop and take the watch to a jeweler rather than force it.

Identify your battery type before you start

The battery type is printed on the inside of the case back—the metal disc on the back of your watch. Look for a code like CR2032, CR2016, SR626SW, or similar. If you cannot read it or the printing is worn away, check your original manual or look up your specific Ironman model number online; Timex publishes battery information for most models on their website.

Do not guess. Buying the wrong battery wastes money and means another trip to the store. Take a photo of the case back with your phone if the printing is hard to read, and show it to the store clerk or search for it online before you leave home.

Gather the right tools

You need one of the following to open the case back:

  • A coin (dime, penny, or quarter—whatever fits the slot snugly)
  • A small flathead screwdriver, usually 1.5 to 2 millimeters wide
  • A watch case opener tool, sold at jewelry stores and online for five to ten dollars

That is all. You do not need a magnifying glass, special lubricant, or a workbench. A kitchen table and good light are enough. If you wear glasses, put them on; the battery is small and the metal holder has a tiny lip you need to see.

Open the case back

Look at the back of your watch. You will see either a slot (for a coin or flathead screwdriver) or a small Phillips screw. Most Ironman models use a slot.

For a slotted case back: Insert your coin or flathead screwdriver into the slot and turn counterclockwise—the same direction you unscrew a jar lid. Turn gently; you are not forcing it. The case back will loosen and pop free. If it does not budge after a quarter turn, stop. Do not force it. A stuck case back usually means it is sealed or the slot is stripped, and forcing it can damage the watch.

For a Phillips screw: Use a small Phillips screwdriver and turn counterclockwise. Again, gentle pressure. One full turn should loosen it enough to unscrew by hand.

Once the case back is loose, lift it straight off. Set it aside where you will not lose it—the screw or the case back itself is straightforward to misplace on a kitchen table.

Remove the old battery and install the new one

Inside the case back, you will see a metal battery holder—a small circular or rectangular frame with a raised lip on one side. The old battery sits in this holder. Using your fingernail or the edge of a coin, gently pry the battery up by lifting on the edge opposite the lip. It will slide out easily; if it does not, you are prying in the wrong spot.

Before you touch the new battery, note which side is which. The flat side with a plus sign (+) is the positive terminal; the flat side with a minus sign (−) is the negative terminal. The positive side must face up toward the watch face. Slide the new battery into the holder with the positive side up, and press it down gently until it sits flat. You will hear or feel a small click when it seats properly.

That is the entire battery replacement. Do not worry about the battery being loose; the metal holder holds it firmly in place.

Close the case back and test the watch

Line up the case back with the watch body. If there is a slot or screw, align it so the slot or screw hole matches. Press the case back down gently and turn clockwise—the opposite direction from when you opened it—until it is snug. Do not overtighten; you are sealing the watch, not clamping it in a vise. A quarter turn past snug is enough.

Press a button on the watch face. The display should light up or respond normally. If nothing happens, the battery may not be seated correctly. Open the case back again, lift the battery out, and reseat it, making sure the positive side is facing up and the battery is sitting flat in the holder.

When to take your watch to a jeweler instead

Stop and take the watch to a jeweler if any of these things happen:

  • The case back will not budge after a gentle quarter turn with a coin or screwdriver.
  • The slot or screw is stripped—the tool spins without catching or the screw head is damaged.
  • The case back is sealed or glued shut (some older or waterproof models are).
  • The battery holder is damaged, cracked, or the battery will not stay in place.
  • The watch still does not work after you have reseated the battery twice.

A jeweler can open a stuck case back without damaging the watch, replace a damaged battery holder, or diagnose a deeper electrical problem. The cost is usually ten to twenty dollars for a battery replacement, which is still cheaper than buying a new watch.

Frequently Asked Questions

Can I use any CR2032 battery, or does it have to be a specific brand?

Any CR2032 battery works. Brand does not matter—Duracell, Energizer, store brand, and others all perform the same way. Buy whatever is cheapest at your drugstore or supermarket. The only exception is if your manual specifies a silver-oxide battery (SR626SW, for example) instead of alkaline; in that case, stick to that type, as they have slightly different voltage.

What if the battery is stuck in the holder and will not come out?

Do not pry hard. Gently work a coin edge or plastic spoon under the battery edge and rock it back and forth slightly. If it still will not budge after a minute of gentle rocking, stop. A stuck battery usually means corrosion inside the holder, which a jeweler can clean out safely.

How often do Timex Ironman batteries need replacing?

Most CR2032 and CR2016 batteries last two to three years in a Timex Ironman, depending on how often you use the backlight and alarm features. Silver-oxide batteries (SR626SW) last longer, often three to five years. You will know it is time when the display dims, the backlight stops working, or the watch stops keeping time.

Is it safe to open the watch if it is waterproof?

Most Timex Ironman watches are water-resistant to 100 meters or more, and opening the case back does not affect that rating as long as you close it properly. The seal comes from the case back gasket, not from the case being permanently sealed. After you close the case back, your watch remains water-resistant at its original rating.

What should I do with the old battery?

Take it to a battery recycling program. Most drugstores and electronics retailers (Best Buy, for example) have battery drop-off bins near the checkout. Do not throw it in the trash. Batteries contain materials that can leak into soil and water if they end up in a landfill.