Is roaming in Gibraltar included with my UK (O2, EE, Vodafone) SIM card, or should I use a CoreESIM?

Despite being a British Overseas Territory, Gibraltar is not considered part of the UK for mobile roaming purposes by most UK carriers. Post-Brexit, many UK networks, including O2, EE, and Vodafone, have excluded Gibraltar from their free roaming zones. Expect to incur costly 'Day Pass' or per-MB charges. CoreESIM offers a specific, transparent data plan for Gibraltar, circumventing these high roaming costs.