Hello Ward-,
Thanks for reaching out to Apple Support Communities. We see you have some questions about your Apple Watch competitions when traveling, and we'd like to help.
Your competitions will track as normal, even though you will be in another region. The following link can help explain how sharing your Activity works.
As long as your Apple Watch and iPhone stay paired, you'll be able to keep up with your Activity.
Let us know if this helps.
Share your Activity and compete with friends with your Apple Watch - Apple Support
Regards.