This time the police made the arrest of an 18 year old youth in Llanelli, Wales.
The young man was bailed until March next year. The four other people were also released on police bail after arrests following the hack in late October.
They are all charged with breaking the Computer Misuse Act and police enquiries continue.
After the hack, CEO Dido Harding received a ransom demand. Initially, TalkTalk thought millions of accounts had been hacked but it later vastly reduced the numbers.