How can I check if connection to Sql Server is encrypted?

In SQL Server I can "Force Encryption" in protocols settings. If I leave that set to "No" any client can still require encryption.

Can I somehow see what connections to the database are using encryption?

From TechNet sys.dm_exec_connections DMV: the encrypt_option will display FALSE if the connection is not encrypted.

Here is an example TSQL statement that can be run by administrators (VIEW SERVER STATE is the required privilege):

SELECT session_id, connect_time, net_transport, encrypt_option, auth_scheme, client_net_address 
FROM sys.dm_exec_connections

StackExchange Database Administrators Q#117873, answer score: 24