The Blue Planet: Copenhagen's National Aquarium Explained

What Is The Blue Planet?

Den Blå Planet, officially the National Aquarium Denmark, is Scandinavia's largest aquarium. It opened in Kastrup in March 2013. The current building covers roughly 12,000 square meters and holds approximately 7 million liters of water spread across 53 individual exhibits. Inside, around 20,000 animals representing some 450 species are on display, from small freshwater fish to large sharks circling a large ocean tank.

The aquarium sits on the western shore of the Øresund Strait in Kastrup, the same district that contains Copenhagen Airport. The location is deliberate: the architects and curators wanted visitors to understand that the sea surrounding Denmark is not an abstract concept but a living, visible neighbor.

The Architecture: Worth Noticing Before You Go In

The building itself, designed by the Danish firm 3XN, was completed in 2013 and became an immediate reference point in Scandinavian architectural circles. Its form is based on a whirlpool or vortex, with five curved wings spiraling outward from a central hub. The facade is clad in aluminum shingles that overlap like fish scales, changing tone from silver-grey to near-white depending on light and cloud cover. On an overcast morning, it looks almost monochromatic. In low afternoon sun, the surface catches the light in small fragments.

If you arrive by the waterfront path from Kastrup Metro station, you approach the building from its most dramatic angle. Spend a few minutes walking the perimeter before entering. The structure is discussed further in our guide to Copenhagen's design and architecture, which places it in the broader context of the city's built environment.

Inside the Aquarium: Moving Through the Exhibits

The interior circulation follows the building's spiral logic. You move from smaller freshwater environments toward progressively larger marine habitats, with the enormous ocean tank as the climax of the route. This progression works well: by the time you reach the main tank, your eyes have adjusted to the low ambient light that most exhibits require, and the spatial shift from intimate tunnel viewing to open two-story viewing panels feels genuinely striking.

The freshwater sections cover tropical rivers, cold Nordic streams, and rainforest zones where small fish and amphibians share carefully controlled microclimates. The humidity in the rainforest section is noticeable. Condensation forms on the viewing glass. The smell shifts between the zones in ways most aquariums avoid: earthy and warm in the freshwater tropics, cooler and faintly saline near the marine tanks.

The coral reef exhibits are among the more visually dense sections, with color contrasts that are difficult to photograph well in the dim light. The ocean tank, by contrast, is large enough to photograph effectively: sharks, rays, and large schooling fish move through a space with enough depth to create a sense of open water rather than confinement. A tunnel passes through the base of the tank, carrying visitors through slowly. Children tend to stop moving entirely here, which creates mild bottlenecks during peak hours.

What to Prioritize if Time Is Short

• The main ocean tank and its tunnel: this is the centerpiece and worth taking slowly.
• The feeding schedules posted at the entrance: timed feeds in certain tanks draw small crowds but offer unusual close-up views.
• The freshwater section if you have children: the interactive zones here are better calibrated for younger visitors than the larger marine halls.
• The exterior terrace near the waterfront: often overlooked, it offers a clear view across the Øresund and a place to decompress mid-visit.

When to Visit and What to Expect at Different Times

Weekday mornings between 10:00 and 12:00 are consistently quieter. School groups arrive frequently on weekday mornings from autumn through spring, so late morning can become unexpectedly crowded near the educational zones. Arriving right at opening on a Tuesday or Wednesday gives you the best chance of moving through the main tank tunnel without waiting.

Saturday and Sunday afternoons between 13:00 and 16:00 are the busiest windows. The central atrium fills quickly, and the tunnel walkway queues. If a weekend visit is your only option, arrive at opening and move immediately toward the ocean tank before the crowd catches up.

Monday evenings are a specific opportunity. The aquarium stays open later on Mondays during some periods, while hours vary by season on other days. By 18:00 on a Monday, visitor numbers can drop substantially. The lighting in the larger tanks takes on a different quality in the evening: the ambient darkness outside the building deepens the contrast with the illuminated water, and the overall atmosphere is calmer.

Getting There: Transit and Practical Logistics

The most straightforward route is the Metro to Kastrup station, followed by a short walk to the aquarium. The Metro M2 line connects the city centre directly to Kastrup, passing through Copenhagen Airport. From Kongens Nytorv, the journey takes roughly 20 minutes. Ticket prices for Metro travel are zone-based and should be verified before travel.

If you're using public transport across multiple attractions in a day, the Copenhagen Card covers Metro fares and includes free entry to the aquarium, which makes it financially straightforward if you're visiting several paid attractions. For more detail on navigating Copenhagen by transit, our transit guide covers routes, zones, and ticket options.

By car, the aquarium is accessible via the E20 motorway with parking available on site. The drive from central Copenhagen takes around 15 minutes without traffic. Note that parking fees apply and the lot fills quickly on peak days.

Photography, Accessibility, and What to Bring

Photography inside is permitted without flash. Most exhibits are kept intentionally dim to reduce stress on the animals and maintain natural light cycles. A smartphone with a reasonably good low-light camera will handle the majority of situations, but a dedicated camera with a wide aperture performs noticeably better in the tunnel and coral sections. Video is popular here: the slow movement of large pelagic fish through the ocean tank transfers well to short video clips.

The building is modern and designed to meet contemporary technical standards for public access. For specific accessibility details, including wheelchair routes, lift access, companion ticket policies, and disabled parking, check the visitor information section of the official website before your visit.

There is a cafe and restaurant inside, and lockers are available for bags. On busier days, the cafe lines are long by midday. Bringing a water bottle is practical. The building maintains a consistent internal temperature year-round, so outdoor clothing layers that can be removed are useful in summer.

Honest Assessment: Is It Worth the Trip to Kastrup?

The Blue Planet is further from central Copenhagen than most major attractions, and the admission fee is not trivial. For travelers with limited time in the city, the case for going depends on what you're comparing it against. If you're traveling with children, the scale, variety, and pacing of the exhibits make it one of the better half-day options in greater Copenhagen, better calibrated for younger visitors than, say, the collections at the National Museum or the SMK National Gallery.

For adults traveling without children, the aquarium is worth visiting if marine biology or Nordic architecture interests you, or if you have a Monday evening free. For travelers with only one or two days in Copenhagen focused on the historic centre, it is probably not a priority. The building is genuinely worth seeing, but it doesn't need to compete with Rosenborg or Christiansborg for your afternoon.