Venice Atienza’s wistful and evocative documentary is rooted in the liminal space between childhood and adolescence. Having grown up in Karihatag, a remote fishing village in the south of the Philippines, 12-year-old Reyboy is about to leave for the big city, where he will be attending high school. His last days at the seaside are punctuated by everyday routines as well as grand existential questions that can only be asked by the very young – such as, what lies beyond the glittering stars?

Reyboy’s love for his hometown, where mobile phone signals have not yet reached, is vividly portrayed. Through his eyes, every part of this picturesque oasis holds a world of magic, from underwater corals to the smallest pebble. Here, the fishermen share their catch of the day among the villagers; the practice is so matter-of-fact to Reyboy that he cannot comprehend the harshness of metropolitan life, where people are left to fend for themselves.

Diaristic in its observations of a vanishing way of life, Atienza’s moving voiceover effortlessly shifts between her private contemplations and her conversations with Reyboy; it is a juxtaposition that erases the distance between film-maker and subject. It seems that Atienza, too, is going through her own metamorphosis, falling under the spell of Karihatag. Drinking in the mesmerising vistas of blue waves and crimson sunsets, the camera avoids reducing Karihatag to a romanticised idyll, or a travel postcard. As the ocean dumps heaps of plastic waste on the quiet shore, the alarming sight of environmental destruction renders the village’s beauty – and Reyboy’s innocence – fragile. Even though Reyboy and Atienza promise to reunite in Karihatag, their bittersweet goodbye trembles with a melancholic finality – many leave for better opportunities, never to return.

• Last Days at Sea is available from 22 September on True Story.