Yes, but only to the Green Zone. It is run by the Turkish government, it is open to the public and it needs no badge. The Blue Zone, where the negotiations and the pavilions are, is closed to anyone without UN accreditation.
There is no way to buy a Blue Zone badge and no route for an individual to register alone. Accreditation comes through a country delegation, an admitted observer organisation, the media, or the UN itself. If you are not already attached to one of those, that door is shut for 2026, because observer admission takes years rather than months.
The Green Zone is a real venue with its own programme, not a consolation prize. At Antalya it sits on the same site as the Blue Zone with its own entrance, and it carries the startup zone, the art programme and the academic programme. In Belém, 700,000 people passed through the COP30 Green Zone in the two months before the conference opened.