Yes, a 5G SIM card from one carrier can function on another carrier's network, but there are a few considerations:
* Compatibility and Functionality: In most cases, modern SIM cards, including those designed for 4G/LTE, are forward compatible with 5G technology[4]. A 4G SIM card can work in a 5G phone, providing connectivity and transmission[4]. Likewise, a 5G SIM can be used in a 4G phone, but it will default to the best network the phone can handle[4].
* Carrier Requirements: Some carriers may request that you upgrade to a 5G-specific SIM card for enhanced services, like T-Mobile's Standalone 5G[4].
* Unlocked Phones: To use two different carriers on a dual SIM iPhone, the phone must be unlocked; otherwise, both plans must be from the same carrier[2].
* Device Support: The device itself has to be supported by the provider[6].
* Dual SIM Use: Dual SIM phones allow you to use two different networks on the same phone and switch between them easily[2]. Some enterprise routers use dual 5G SIMs from different carriers to improve link reliability[8].
Citations:
[1] https://trustedconnectivityalliance.org/technology_overview/5g/
[2] https://discussions.apple.com/thread/251960086
[3] https://simu5g.org
[4] https://www.yournavi.com/posts/5g-sim-card
[5] https://www.ericsson.com/en/ran/carrier-aggregation
[6] https://community.oneplus.com/threads/5g-works-with-other-carriers-but-not-with-mine.1519781/
[7] https://info-nrlte.com/tag/cross-carrier-scheduling/
[8] https://support.huawei.com/enterprise/en/doc/EDOC1100130782/dfe37171/example-for-configuring-an-enterprise-to-access-the-internet-through-dual-5g-sim-cards