Quick & Simple: How to Replace Your Seiko Watch Battery

Seiko has been making watches since 1881 and has an excellent pedigree; producing the first quartz watch in 1969 and the first LCD watch in 1973 – you must have owned one if you were a kid in the 70s/80s.

Today, Seiko has a large range of watches with different mechanisms, but they do not all require a battery.  Make sure your watch is not an automatic model like the Seiko 5, Seiko Prestage, and Seiko Spirit Automatic Classic Magnum – these are all self-winding.

manual seikos do not require a battery
Automatic Seiko – no battery required

If you are happy that your Seiko watch does require a battery and your watch has stopped working, then this guide is for you.

How to Replace a Seiko Watch Battery

Most of the Seiko watches that require a battery all have a similar method of replacing them, although you will need to check the chart for the specific battery model.

At the bottom of this article, I have also included a battery serial number chart for common batteries.

Tools Required

The first is to make sure you have the appropriate tools. You don’t want to damage your watch in any way.

Here are some tools you must have: –

  • Tweezers
  • A sharp knife that will open the watch case
  • Watch wrench (not essential) or rubber ball
  • A piece of soft cloth
  • Small screwdriver

A dedicated watch wrench back remover will make life much easier if you have a sizeable watch collection, these can be bought online for very little money.

Watch Wrench Back Remover taking the back off a Seiko

Understand that not all Seiko models work exactly the same way. There might be slight variations, so you need to understand the exact product to choose the best tools.

> Michael Kors Watch Battery Replacement Guide

Replacing the Battery

Step 1: Undo your Seiko watch strap

You need to undo the watch strap so you can easily get access and work on the back case. Use a pin or your tweezers to release the pin shown in the image below.

Image showing how to release a Seiko watch strap so you can lay it flat

Step 2: Prepare your workspace

Place your soft fabric on the table and lie on it with your Seiko watch facing down. The aim of the fabric is to prevent the watch from getting any scratches.

Ensure there are no sharp items on the cloth or on the table. Some watches are quite sensitive.

Step 3: Remove the back of the Seiko watch

Most Seiko watch backs have to be rotated anti-clockwise to remove them.  Look for the grooves on the back of your watch.

Back of a Seiko Prospex SNR045J
Image source: Time and Tide, Graphics by Kiko

The watch has a screw back if it comes with grooves like in the image above. If you have a watch wrench, use the steps below otherwise skip these steps and watch the video showing you how to remove the back with a rubber ball.

  • Properly set the prongs on the wrench to fit the three prongs outside the watch’s case. You can add a piece of plastic over the back to help protect the watch from being scratched by the wrench.
  • Tighten the prongs properly.
  • Twist the handle on your wrench anti-clockwise by half a turn. This will ease the back of the case so you to open it faster.
  • You can use your hands from here to unlock the case.

If you are concerned about removing the back or don’t have the correct tool, it can be done with a rubber ball. Check out this video from helpful DIY.

If the back of the watch does not have grooves, it has a snap back. Now for this, you will need to check your screwdrivers to pick the one that fits the case.

Tilt the screws until the back case is completely loose. Once done, lift off the case, and you will see the watch mechanisms.

Note: You can remove the back using only a Phillips screwdriver and inserting the head into a single groove, it’s just a little tricky. I’ve attempted this before but the screwdriver slipped and cut my finger.

Step 4: Remove the rubber gasket

Some watches have a rubber gasket, which keeps the watch waterproof. Be careful not to pull out the entire piece that attaches to the watch’s face, as it can destroy the hand.

You will need to replace it carefully using the right tool once the work is done. This part should not be hard to notice if you have had occasional strap changes.

Step 5: Locate the battery

Most Seiko watch batteries are held in my metal catch. This needs to be flipped up gently with a pair of tweezers so the battery can be removed.

Go to 3:17 in this video to see how the cast should be lifted.

I have also seen the battery being removed with Blu Tack.  Wrap a pen tip with blu tack so it’s in a ball, then gently press it onto the battery to lift it out.

Step 6: Insert the new battery

This is where a pair of tweezers will be helpful. Fit the new battery in the same position as the last one. Ensure the battery’s edge is touching each side carefully to allow for a proper power supply.

Step 7: Closing up

You can now prepare to close the watch’s back. This is another step where you need to be very careful.

Start by inserting the rubber gasket (if it had one) in the exact manner you found it.

Make sure the metal battery holder is pushed back down and screw the watch back onto the body in a clockwise motion.  If the back does not have the screw fitting, snap it back onto the body until it clicks.

Step 8: Resetting your Seiko watch

Now that you have a new battery installed, reset all the time and date functions by consulting your manual.


Seiko watch battery finder by serial number

Below are two charts for high and low-drain batteries that are used in Seiko watches.

How to use this Seiko watch batteries chart

  • Once you have removed the back of your watch, check the serial number of the battery.
  • The chart shows the equivalent battery in different brands, so you can easily buy a replacement Seiko battery from any Walmart or online.
Seiko battery chart
Low drain battery chart for Seiko watches
battery chart
high drain battery chart for Seiko watches