Gauci and Melbourne City shot-stopper Beach are among 10 additions to national team boss Tony Popovic's camp in Florida, announced on Monday.
On loan at Port Vale from Aston Villa, Gauci had started matches in Popovic's first window as coach, but fell out of favour behind captain Mat Ryan and Paul Izzo.
The 25-year-old last appeared in a Socceroos squad in October, left as an unused substitute in friendlies against Canada and the US.
Gauci's starring performances to help English League One outfit Port Vale to an FA Cup quarter-final against Chelsea in April have at least convinced Popovic to keep the door open.
But the keeper will face stiff competition from Beach, who had leapfrogged Gauci in recent windows to earn his maiden cap in a 1-0 loss to Venezuela last November.
The 22-year-old heads to Florida after Melbourne City suffered a 1-1 (7-6) elimination-final loss to Auckland FC last weekend.
Beach's City teammate Aziz Behich will also travel to Sarasota, alongside exciting young guns Mohamd Toure and Nestory Irankunda.
City phenomenon Marcus Younis, 20, was overlooked in Monday's announcement, with Young Socceroos pair Daniel Bennie and Raphael Borges Rodrigues handed their maiden senior national team call-ups.
Former Perth Glory winger Bennie plays for Queens Park Rangers, while Dutch-born former City winger Rodrigues is on loan at Wigan Athletic from Coventry City.
More players will enter camp across the coming weeks, with 2022 World Cup heroes Harry Souttar and Mathew Leckie already in Florida.
The Socceroos play a friendly against Mexico in Los Angeles on May 31 - the last game before Popovic selects his squad on June 1 - before relocating to their Bay Area base.
SOCCEROOS TRAIN-ON SQUAD: Aziz Behich, Patrick Beach, Adjin Hrustic, Cameron Burgess, Mohamed Toure, Nestory Irankunda, Daniel Bennie, Raphael Borges Rodrigues, Alex Robertson, Joe Gauci
* Announced last week: Harry Souttar, Hayden Matthews, Anthony Caceres, Mitch Duke, Brandon Borrello, Nick D'Agostino, Nishan Velupillay, Mathew Leckie
9°C