Like every other developer beta from past couple of years, it's likely that Apple will make iOS 11.3 beta 1 available soon to
those public testers registered on Apple Beta Software Program portal as well in a couple of days time max.
Not exact matches
As you may already know, Apple has been issuing iOS 11.3 pre-release seeds to
registered developers and
public testers for quite some time now in the hope of getting the firmware up to the relevant standard for a global
public release.
The first beta is currently live only for
registered developers, but
public testers should also be able to get their hands on this release in the coming days.