You can see the current list of countries where Claude is available here: https://www.anthropic.com/claude-ai-locations.
If Claude 3 Opus is not publicly available in any member states of the EU by 2024-05-01 00:01 AM UTC+00, this market will resolve NO.
If (and when) I confirm it to be publicly available in ANY of the 27 member states of the European Union, this market resolves YES (even if they haven't updated that list yet).
Any version of Claude 3 Opus counts for the purposes of this question. (API, web interface, any future version called "Claude 3 Opus") If even one of those is available (publicly, by the above date, in the correct country), this resolves YES.
If it becomes publicly available, but then becomes blocked again afterwards, such that it's still blocked on May 1st, the market will still stay YES.
Requiring a paid user subscription does not disqualify its status as "publicly available".