Naturum Koster and the Koster Islands – A Day Trip in Kosterhavet National Park from Strömstad
Family-Friendly Day Trip with Selin Charter – Hiking, Lighthouse Visit and Seal Safari on the Koster Islands
Join Selin Charter on an unforgettable boat trip into Kosterhavet – Sweden’s first and only marine national park. Along Bohuslän’s dramatic coast, a maze of islands, islets, and skerries spreads out before the horizon opens to the mighty Skagerrak. Beneath the surface lies one of the country’s most unique ecosystems, where the Koster Trench plunges to 247 meters and thousands of species coexist in a world few get to experience up close.
At the heart of this natural gem lies Naturum Koster – the gateway to Kosterhavet National Park. Here you can discover the secrets of the sea through aquariums, films, and interactive exhibitions that fascinate both children and adults. You’ll encounter kelp forests, colorful corals, and a rich marine life presented in a way that makes it easy to understand why Kosterhavet is so unique. Daily film screenings offer an even deeper insight into this remarkable marine environment.
When you step ashore on the Koster Islands, you are welcomed by experiences that combine both nature and cultural history. Follow marked hiking trails, swim in a secluded bay, or immerse yourself in the history of the national park. If you want to experience even more, you can combine your trip with other excursions – such as a seal safari to Ursholmen, where Bohuslän’s seals bask in their natural habitat.
At Selin Charter, we are proud to be an official host company for Kosterhavet. This means we not only bring you smoothly from Strömstad to South Koster (Ekenäs) – we also share our local knowledge and guide you to some of the park’s most beautiful places. The adventure begins already on board: the boat trip offers salty breezes, sparkling seas, and granite cliffs framing Bohuslän’s most stunning archipelago views. To make the journey even more enjoyable, you can pre-order something tasty to eat – a smoked sandwich with hand-peeled shrimp, a classic ham-and-cheese roll, or a freshly baked cinnamon bun with coffee. Beer and wine are also available on board, for those who want to add a little extra sparkle to the excursion.
Ticket booking
Online booking through the form.
Travelinformation:
naturum Koster Sea sydkoster From Strömstad
Find here
- From: Strömstad, Norra Hamnen
- Experience: Naturrum Koster sea
- Time: 45 minutes
- Boat: M/S Kosterskär
Other information
– Requires pre-booking of food and tickets.
– Family price includes 2 adults and 2 children.
– Children under 4 years travel free of charge.
– Pre-order meals for larger groups and events.
– Beer and wine are sold on board with full license.
– Light refreshments and snacks are available on board.
– Toilet facilities are available on board.
– We welcome bus groups from May to October.
– Our boats can be chartered according to your schedule and needs.
– Subject to weather conditions.
– Bicycles are not allowed on board.
Schedule Summer 2025
Timetable: Tuesday, Thursday, Saturday
Period: 28 June - 9 August
- Experience: Naturum Kosterhavet på Sydkoster
- Travel time: appr. 45 minutes
- Departue, Strömstad: 10:00 AM - arrival appr. 10:45 AM
- Return, Ekenäs: 15:00 PM - arrival appr. 15:45 PM
v 26:
Strömstad: 28/6
- 10:00 AM - North harbour
Koster: 28/6
- 15:00 PM - Ekenäs
v 27:
Strömstad: 1, 3, 5/7
- 10:00 AM - North harbour
Koster: 1, 3, 5/7
- 15:00 PM - Ekenäs
v 28:
Strömstad: 8, 10, 12/7
- 10:00 AM - North harbour
Koster: 8, 10, 11, 12/7
- 15:00 PM - Ekenäs
v 29:
Strömstad: 15, 17, 19/7
- 10:00 AM - North harbour
Koster: 15, 17, 19/7
- 15:00 PM - Ekenäs
v 30:
Strömstad: 22, 24, 26/7
- 10:00 AM - North harbour
Koster: 22, 24, 26/7
- 15:00 PM - Ekenäs
v 31:
Strömstad: 29, 31/7, 2/8
- 10:00 AM - North harbour
Koster: 29, 31/7, 2/8
- 15:00 PM - Ekenäs
v 32:
Strömstad: 5, 7, 9, 16/8
- 10:00 AM - North harbour
Koster: 5, 7, 9, 16/8
- 15:00 PM - Ekenäs
- 16/8, 11:00 PM - Ekenäs
From Mainland to Island Paradise – A Visitor’s Guide to the Koster Islands
When you step ashore on the Koster Islands, you arrive at a place where life flows in harmony with the sea. Rugged cliffs and blooming coastal meadows blend with small communities that still carry traces of generations of coastal living. Daily life here is marked by calm and simplicity, where bicycles replace cars and time seems to move at a slower pace. At the same time, nature is always close at hand – from seabirds calling overhead to waves breaking against the granite rocks.
For the curious visitor, a wide spectrum of experiences awaits: hike along marked trails and discover panoramic views over the Skagerrak, swim at family-friendly sandy beaches, follow an underwater snorkeling trail, or explore the islands’ living cultural heritage. To deepen your understanding of Kosterhavet’s unique ecosystem, begin your journey at Naturum Koster, while a visit to the Ursholmen lighthouse station gives you a sense of history and the life of the lighthouse keepers who once lived there.
Whether you seek peaceful relaxation, sea adventures, or insights into coastal culture, the Koster Islands offer an experience where nature and culture intertwine – a journey that will stay with you long after you have returned to the mainland.
Naturum Koster – Discover Marine Life in the Skagerrak, Kosterfjord and Koster Trench
The Sea that Shapes Kosterhavet
Kosterhavet is part of the mighty Skagerrak, where the depths reach down to around 700 meters. Here, vast Atlantic waters are pressed towards Bohuslän’s coast. The water is oxygen-rich and full of nutrients, creating conditions for an unusually large number of species. It is this inflow from the open ocean that makes Kosterhavet National Park one of the most biodiverse places in Sweden.
Kosterfjord – The Link Between Depths and Coast
Stretching between the Koster Islands and the mainland, Kosterfjord acts as a vital corridor between the deep waters of the Skagerrak and the coast. Oxygen- and nutrient-rich water flows inland through the fjord, enabling species that normally thrive in the deep sea to live close to the Swedish coast. The combination of deep-sea and coastal habitats creates a marine landscape found nowhere else in the country.
The Koster Trench – Sweden’s Deepest Marine Ravine
At the heart of Kosterfjord lies the Koster Trench, a dramatic underwater canyon plunging to 247 meters. Here, coastal fish coexist with deep-sea species, and it is one of the few places in Sweden where cold-water corals form reefs. Thanks to this unique environment, more than 6,000 species live here – from lobsters and shrimp to starfish and rare sponges. The Koster Trench is therefore one of the most valuable marine environments in all of the Nordic region.
Naturum Koster – The Gateway to the National Park
To understand the interplay between the Skagerrak, Kosterfjord, and the Koster Trench, Naturum Koster is the perfect starting point. Marine life is presented here through aquariums, interactive exhibits, and films that provide both children and adults with a fascinating glimpse into the hidden world of the sea. Naturum serves as a living gateway to Kosterhavet National Park, showing why this area is so unique – and why it is so important to protect.
Experience the Koster Islands – Activities, Beaches and Cultural Gems for the Whole Family
Hiking on North Koster and South Koster
The Koster Islands are made for hiking. On North Koster, marked trails lead you through rugged cliffs, boulder fields, and viewpoints where the sea stretches endlessly toward the horizon. South Koster offers softer landscapes with blooming coastal meadows, small farms, and leafy forests. A highlight is Valfjäll, South Koster’s highest point, where you are rewarded with panoramic views over the entire Kosterhavet National Park.
Cycling in a Car-Free Archipelago
On South Koster, you can easily rent a bike and explore the island along winding roads. You’ll pass coastal meadows, small cafés, and local studios. With no cars on the islands, cycling is both safe and relaxing – perfect for families or anyone wanting to see more in less time.
Beaches and Snorkeling in Clear Waters
The Koster Islands boast some of Bohuslän’s finest beaches. Kilesand on South Koster is ideal for families thanks to its shallow waters and soft sand. On North Koster, Basteviken offers a quiet swimming bay with crystal-clear water. For those eager to explore beneath the surface, the snorkeling trail at Rörvik is a unique adventure where you can follow a marked underwater path and encounter Kosterhavet’s marine diversity up close.
Kayaking Among Islands and Skerries
Gliding through the waters in a kayak between islets and skerries offers a perspective unlike any other. Kayaking brings you close to nature, where you can spot seabirds up close – and perhaps even meet a curious seal popping up beside you.
World-Class Birdwatching
The Koster Islands are home to a rich birdlife. Here you can see cormorants, sea eagles, eiders, and terns in their natural habitats. Several areas of North Koster are recognized as important nesting grounds for seabirds, making the islands a favorite destination for birdwatchers from around the world.
Strömstad’s Culture Award 2020 and Strömstad’s Tourism Award 2022 were awarded to Helena Lantz, who runs Selin Charter.
The 2020 jury’s motivation read:
“This year’s Culture Award is presented to Helena Lantz, who runs the popular visitor destination Hilmas Alaska on Nord-Långö.
With great drive and an enormous commitment to keeping a unique cultural heritage alive and preserving local history, Helena Lantz is awarded the prize. The work she puts into making the garden flourish in its finest form is invaluable. Through her efforts, the memory and history of Hilma Svedahl live on.”
So appreciated – thank you so much!
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