How to Replace the Battery on My Timex Marathon Watch

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The Timex Marathon is a digital sports watch that includes convenient calendar, alarm and stopwatch functions. Change the battery in your Timex Marathon when the digital display grows faint or if the watch stops.

The battery replacement process for Timex Marathon watches is simple, straightforward and takes just minutes.

Remove the pressure-sealed back of your Timex Marathon watch using a three-tipped watch case opening tool. Adjust the tips of the case opening tool to line up with the notches on edges of the watch back. Fit the tips of the tool in the corresponding notches and rotate the knob at the end of the case opening tool to tighten its grip on the watch. Use the tool to apply moderate pressure to the watch while simultaneously twisting the tool to the right; the back of the watch will pop free. Set it aside.

Use a small pair of needle-nose plastic tweezers to lift out the protective rubber gasket and plastic plate that covers the battery compartment. Work carefully to avoid damaging these components; they are essential to maintaining your watch's water resistance.

Remove the old watch battery from the battery compartment using the plastic needle-nose tweezers. Throw the old battery away or recycle it at the appropriate facility.

Fit a new battery into the battery compartment of your Timex Marathon. Observe the correct polarity when putting in the new watch battery.

Touch the small AC pad to the left of the battery compartment with the tip of a straightened paper clip to activate the watch's internal reset switch.

Replace the protective plastic plate, followed by the protective rubber gasket. Apply moderate pressure to the back of the watch until it snaps into place.