This is a 1st generation watch or Series 0,if you phone has ios13 then it will be very difficult to pair because this watch in technology terms is very old.Your watch will only update to watchOS4.The latest version of watchOS is 6 at the moment.
Read this to see what you may be in for.
This is becoming a bigger problem every day,ios13 doesn't seem to like watches with watchos5 or below,here are the solutions from other forum members.
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Apple watch 2;
I found a friend, who was on iOS 12 and used his iPhone to pair. Before pairing it asked to upgrade the watch OS (iOS 13 didn't offer this option). After I upgraded the watchos I unpaired the watch from the ios12 phone and then was able to pair it with any iPhone running iOS 13.
Quote;
1st gen apple watch;
pairing was successful on the following device (with associated OS)
to pair via bluetooth I used an iphone 7 with iOS 12, after pairing immediately accepted the watchOS update to version 4.3.2 after everything was successfully equipped with the last update, unpaired the iPhone and the Apple Watch a reset (factory settings) all this took some time but afterwards pairing on an iPhone XR with iOS13 g was a piece of cake.
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May 9, 2020 4:58 AM in response to Hashimsabbah
Just did this with a series1. I had to pair with the original phone and update the firmware for me to pair correctly. All I did was ask to pair and the update happened on an iPhone 6.
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Jan 28, 2020 7:48 PM in response to Jimmycon
I ended up having to reboot my entire watch. Clear it and then connect to an older phone that was running OS 12- resyncing my watch with that phone. Updating the apple watch through that phone and THEN removing the sync with the old phone- resyncing to my current iphone 11.....that worked. I hate apple
Find a phone with ios12 on it if you can and pair your watch to it,it will ask you to update the watch select yes,after it has updated unpair the watch from the ios12 phone and then pair it with your ios13 phone.
Now you can update to watchos6.
