Listen to this article
After joining Trident following two seasons in European Formula 3, Piquet Jr. took two wins and four podiums in his maiden GP3 season in 2018.
He finished sixth in the championship, just behind teammate David Beckmann. It was a season his father said had turned Pedro "from a kid into a man".
The 20-year-old sticks with the team in what is a new championship, formed by merging GP3 and European F3.
Piquet drove the series’ new car – which shares many parts with the old GP3 car – at its first shakedown with teams on February 20 at Magny Cours.
“I am really motivated for the season ahead,” said Piquet.
“I experienced a great 2018 season with them, scoring two wins and several podium finishes.
“For 2019 I am sure that we have everything we need to do even better and challenge for the title.”
Trident team boss and 2006 European and Italian F3000 champion Giacomo Ricci added: “He will be part of an extremely competitive line-up that has the potential to write a new chapter of our successful history in this championship.”
Alongside Piquet and the already-confirmed Niko Kari, Devlin DeFrancesco has joined the Italian squad to complete its line-up.
Canadian driver DeFrancesco did GP3 with MP Motorsport last year, but failed to score any points with the squad over the 12 races he contested.
He tested for Trident in the Abu Dhabi post-season GP3 test, and drove at the February 20 shakedown alongside Piquet.
"The new car feels quite a bit different to last year," said DeFrancesco.
"We learned a fair few things at the shakedown and I look forward to making more progress at the official test at Paul Ricard.
"It’s going to be a hard year, it’s such a competitive field, but I’m ready to bounce back from a difficult '18.”
Another team completing its F3 line-up on Wednesday was Hitech, which signed Yifei Ye to partner Red Bull junior Juri Vips and Leonardo Pulcini.
Ye, a former French F4 champion, was third in the Formula Renault Eurocup last year, and finished runner-up to Rinus VeeKay in the Asian F3 Winter Series in the off-season.
The first official test for FIA Formula 3 is at Paul Ricard on March 20-21.
Only four seats remain on the grid for 2019. MP Motorsport have all three seats available, while Jenzer Motorsport has one drive remaining.
Jenzer and Hitech both ran just two drivers at the shakedown test on February 20.
MP ran Richard Verschoor – who is testing MP’s F2 car this week – and ex-Campos GP3 racer Simo Laaksonen in that test.
FIA F3 holds shakedown for new 2019 car
MP signs Red Bull junior Lawson to complete F3 line-up