Saints have been in Spain since last Friday afternoon, when they began a 12-day stint training camp in the region of Catalonia.
During that time Mauricio Pochettino's men will play two friendlies against lower-league opposition, the first of which will kick off tonight at 7pm local time (6pm British Summer Time).
Llagostera will play in the Segunda Divsión B in the coming season, having played in the third tier since being promoted the Tercera División in 2011.
Their rise over the last decade has been quite something, having played as low as the eighth tier in 2005 before five promotions in seven years helped them reach their current heights.
Mauricio Pochettino has a 25-player squad with him in Catalonia, though the game is likely to come too soon for Maya Yoshida, who only began pre-season training on Monday.
Emmanuel Mayuka, Adam Lallana, Jos Hooiveld and Guly have all picked up minor knocks during training this week so will be assessed before tonight's game.
New signings Dejan Lovren and Victor Wanyama have been in full training, so could well get some game-time this evening.
Tonight's game is being played at the Estadi Josep Pla i Arbonès, home of Llagostera's neighbours FC Palafrugell.
The stadium has a capacity of around 4,000 and is about an hour south of Saints' base in Peralada. Tickets are priced at 10€ for adults plus an additional 5€ for a seat in the stand. Children aged three-to-12 are priced at 5€.