The Watford Observer says the player is keen to leave as he does not believe he will get regular playing time with the Premier League side.
Navarro had been close to signing with Leganes in the January transfer window, only for the move to fall through at the last hurdle.
Now the club has renewed its interest, but it is unclear if Watford are ready to let Navarro leave.
He only played four times in all competitions since joining the Hornets in June 2018
But it is possible boss Javi Gracia does not want to lose squad depth ahead of the coming Premier League season.