Enciso has joined in a deal reported to be worth 25 million pounds after impressing during his previous loan spell at Ipswich.
The Paraguay international spent six months with the club in 2025 while on loan from Brighton, before returning to France and joining Strasbourg in September.
The winger worked with Gary O'Neil at Strasbourg last season and was delighted to get the chance to reunite with his former manager.
"I really enjoyed my time on loan at the club and I was so happy to see them win promotion back to the Premier League last season," Enciso said.
"I worked with the manager in France last season and the chance to play for him again at a great club like Ipswich is one I'm very excited for."
Enciso, who represented Paraguay at the recent 2026 FIFA World Cup, now returns to an Ipswich side preparing for their Premier League opener against Sunderland on Saturday.
O'Neil has also brought 20-year-old Ivory Coast forward Ouattara to England, with the youngster signing a contract until 2031 in a deal worth a reported 17 million pounds.
The Ipswich boss was pleased to work with Ouattara again after their time together at Strasbourg.
"Abdoul is a talented young player who can play in different positions, so is a very good addition to our squad," O'Neil said.
"We enjoyed working with him in France last season and are delighted to have the opportunity to do so again at Ipswich."
The double move strengthens Ipswich's squad as they prepare for life back in the Premier League after winning promotion last season under Kieran McKenna, who left the club at the end of the campaign.