The purpose of domain locking is to prevent unauthorized changes to your domain name.
The Registries for .ca, .uk and .eu domain names do not offer the domain locking feature and have implemented other security measures to protect your domain name.
.CA Domain Names
.CA domain names require you approve all transfers and critical changes with CIRA, the .ca Registry.
.UK Domain Names
.UK domain names require you request a Tag Change with the current Registrar or directly with Nominet, the .uk Registry, in order to transfer the domain name.
.EU Domain Names
.EU domain names require you approve all transfers with EURid, the .eu Registry.