Is there a a MICS report available to know user logon / logoff activity to a CICS region?
MICS does not provide a specific data element(s) that contains logon / logoff activity for a CICS region.
If your site requires users to sign-on using the CESN command and sign-off using the CESF command then you may be able to calculate this time by looking at transaction type
in one of the MICS files (CICCSU for example) and start time stamp + end timestamp.
If using the MICS SNT component, all of the connections to CICS done nowadays are either through telnet or TCP/IP. You can analyze the 119 records for logon/logoff information.
SNT analyzer - TCPAPI file / if it is telnet access it is TCPSTN