Protecting the Ocean Means Protecting the Future: Mercure Saga Karatsu Resort Hosts a Summer Upcycling Workshop to Learn About the Sea and Environment Through One-of-a-Kind Creations

Staff members of Mercure Saga Karatsu Resort holding beverage caps collected from vending machines and the upcycled products made from them.

NPO Tangshan Farm&Food (Karatsu City, Saga Prefecture; Representative Director: Nozomi Hamaguchi) will host an experiential workshop on marine plastic pollution at the all-inclusive resort hotel "Mercure Saga Karatsu Resort" (4-9-20 Higashikaratsu, Karatsu City, Saga Prefecture), located near "Niji no Matsubara," one of Japan’s three great pine groves, with views of the sea. The workshop will take place on Saturday, August 8, Sunday, August 9, and Sunday, September 20, 2026.

This program allows participants to upcycle (transform waste into new, valuable products) beverage caps collected from the hotel’s vending machines into unique, one-of-a-kind small artworks using on-site molding machines. Participation is free, no reservation required, with sessions limited to six people each and rotating every 30 minutes. It’s a summer initiative where guests of all ages can learn the importance of protecting Karatsu’s ocean through hands-on creation.

Approximately 3,700 beverage caps have already been collected from vending machines within the hotel, and some of these will serve as raw materials for this workshop.

A scene from the upcycling experience using the molding machine. Participants press down the handle to pour melted caps into the mold (photo from a pre-workshop session for hotel staff).

Event Overview

Name: Ocean Conservation Upcycling Experience Workshop

Dates and Times: Saturday, August 8, 2026: 14:00–18:00 Sunday, August 9, 2026: 9:30–11:00 / 14:00–18:00 * The workshop will also be held on Sunday, September 20. Details will be announced after the August events.

Venue: Lobby of Mercure Saga Karatsu Resort (4-9-20 Higashikaratsu, Karatsu City, Saga Prefecture) Eligibility: Guests staying at the hotel (event is exclusive to overnight guests)

Participation Fee: Free (one session per person)

Capacity: 6 participants per session (30-minute rotating slots, on-site registration)

How to Participate: No reservation required. Register on-site at the venue.

Program: Each session begins with a brief lecture on marine plastic pollution, followed by a hands-on upcycling activity using plastic bottle caps as raw materials. While waiting, guests can also enjoy making bracelets using recycled plastic beads. * Experience duration may vary slightly.

Original coasters created from collected caps. Each features a unique marble pattern—no two are alike.

Coasters immediately after being removed from the mold. The colors of the caps become the patterns.

The "small cycle" of vending machine caps being reborn as coasters.

At Mercure Saga Karatsu Resort, where this workshop will be held, an ongoing initiative transforms beverage caps collected from in-hotel vending machines into original recycled plastic coasters.

Beverage caps from vending machines are reborn as coasters used in the hotel. This event allows guests to personally experience the concept of a circular economy—keeping used items in circulation as resources instead of discarding them.

To date, approximately 3,700 caps (about 9.2 kg as of July 2026) have been collected from vending machines at the hotel. Using lifecycle assessment (LCA) coefficients published by Waseda University’s student project Precious Plastic Waseda—a method for quantitatively evaluating environmental impact from raw material sourcing to disposal—recycling this entire volume instead of incinerating it is estimated to reduce CO2 emissions by approximately 20 kg.

Caption: Sorted plastic bottle caps by color, and the coasters and bracelets made from them. The cycle from material to finished product is instantly visible.

What is Marine Plastic Pollution?—What’s Happening in Karatsu’s Ocean Facing the Genkai Sea

It is said that millions of tons of plastic waste flow into the world’s oceans annually, and many plastic items wash up on Karatsu’s shores along the Genkai Sea. At the start of the workshop, a short lecture will introduce the current state of Karatsu’s ocean with photos and invite participants to consider how we interact with everyday plastics. We believe that the surprise of seeing something destined for disposal transformed into something valuable by one’s own hands can spark a personal connection to environmental issues.

Staff assist with operating the molding machine. The process of pressing down together is also a highlight of the experience.

About Precious Plastic Karatsu

NPO Tangshan Farm&Food has introduced "Precious Plastic Karatsu," adapting the Dutch open-source project "Precious Plastic" to Karatsu. The organization grinds and molds collected plastic waste into new products. It has conducted environmental education workshops (ESD: Education for Sustainable Development) at elementary, middle, and high schools, and created planters using about 1,000 bottle caps (exhibited at Fukuoka Flower Show 2026), reaching audiences both within and beyond Saga Prefecture.

Comments from Stakeholders

Mercure Saga Karatsu Resort

"At Mercure Saga Karatsu Resort, we aim to share the charm of the local area with our guests while advancing environmental initiatives in collaboration with the community. Through this collaboration with NPO Tangshan Farm&Food, we will upcycle plastic bottle caps collected from in-hotel vending machines and marine plastic collected from Karatsu’s shores into coasters with new value. We hope this experience allows our guests to learn about the environment and resource circulation in a fun way, creating lasting memories from their stay and inspiring reflection on everyday environmental issues. We will continue working with the local community to promote sustainable tourism."

Kohmei Kojima, Vice Director, NPO Tangshan Farm&Food

"Seeing bottle caps from vending machines reborn into new items within the hotel—this small cycle is something we hope guests take home as part of their travel memories. It could even inspire ideas for summer vacation research projects. We warmly welcome families to join us."

Exterior view of the event venue, Mercure Saga Karatsu Resort (view across the Matsuura River)

Hotel lobby featuring ceiling art inspired by Karatsu’s festival float (Karako).

Venue: Mercure Saga Karatsu Resort

An all-inclusive resort hotel located near "Niji no Matsubara," one of Japan’s three great pine groves, where about one million black pine trees grow across approximately 4.5 km, with direct views of the Genkai Sea. The hotel offers unique stay experiences through experiential programs that incorporate local culture and materials.

Official Website: https://mercure-sagakaratsu-resort.jp/

Close-up of the coaster’s marble pattern. All materials are made from collected plastic bottle caps.

Organization Overview

NPO Tangshan Farm&Food

Headquarters: 3-7-22 Higashikaratsu, Karatsu City, Saga Prefecture

Business Activities: Environmental education (E