Senior players such as Luke Varney, David Norris, Greg Halford and Liam Lawrence have been left at home with the cash-strapped club still looking to sell their high earners.
Instead, manager Michael Appleton has taken a mixture of youth players and trialists on the 10-day trip.
Among the players on trial are former Barnet striker Izale McLeod and ex-Leeds winger Lloyd Sam.
Goalkeeper Simon Eastwood, defenders Mustapha Dumbuya and Jon Harley, midfielders Brian Howard and Simon Gillett and forward Luke Rodgers are also looking to impress.
Pompey play a friendly against Gibraltar on Friday before taking on south-coast neighbours Brighton in Cadiz next Tuesday.