After joining the club again three weeks ago Watson has been quick to add to the Port squad, writes Tom Feaheny.
Andy Parry and Zac Corbett were the latest to join last week.
"I saw Zac last season playing for FCUM against Southport, we’ve had another couple of looks at him since then" Watson told the club's website.
"He fits the criteria, he’s a strong and quick."
Parry re-joins Southport for his third spell at the club, with Watson saying he was an important acquisition.
"Andy was one of the first players we wanted. I know what I get from him. He can play anywhere, right back, centre back, centre mid.
“The fans know him, he was brilliant when he was here and he got sold on my last day to Luton Town, I’m delighted to have him back through the door.”