Short answer
You can climb Mount Pico (2,351 m) only with a licensed guide and a mandatory permit; independent ascents are not allowed. Book through official operators, check weather and fitness requirements, and confirm current rules with the Azores tourism authority or the Pico natural park. The climb is strenuous and often cloudy, so plan a backup day.
General information, not legal or tax advice. Rules and amounts change: confirm with official sources.