IPSW Portal

Choose aProduct→Choose aPlatform→Choose aVersion→ClickDownload

Download 5.1 (16R5584a) for Apple Watch Series 3 (38mm, LTE)

Version:	5.1
Build:	16R5584a
Signed:	No
Size:	0.76 GB
Release Date:	2018-10-15 17:09:47
Upload Date:	2018-10-11 18:19:26

Secure download directly from Apple's servers