# Urdaibai estuary, Spain: what it is and when to go

> Urdaibai estuary is a Biosphere reserve in Biscay, Basque Country, Spain (Urdaibaiko Biosfera Erreserba) (San Cristobal). Interests: Nature and Wildlife. The best time to visit is April to June and September to October. In June there are 15 h 12 of daylight, and in December, 8 h 48. It has articles in 11 Wikipedias, so it is not one of the busiest places in Spain: one to enjoy at a calmer pace. Here is what it is, where it lies, when to come, how to get there and what else is nearby to turn it into a trip.

- Address: https://kokai.app/en/paises/europa/espana/reserva-de-la-biosfera-de-urdaibai/
- Reviewed on: 2026-10-02
- Language: en

## In a nutshell

- **What it is:** Biosphere reserve in Biscay, Basque Country, Spain · Nature, Wildlife
- **Local name:** Urdaibaiko Biosfera Erreserba
- **Where:** Spain
- **Best time:** April to June and September to October.
- **Nearest airport:** MAD Madrid, 326 km as the crow flies
- **Coordinates:** 43.3403, -2.67069

## What it is and where

Urdaibai estuary is a Biosphere reserve in Biscay, Basque Country, Spain (Urdaibaiko Biosfera Erreserba) (San Cristobal). It has articles in 11 Wikipedias, so it is not one of the busiest places in Spain: one to enjoy at a calmer pace.

It is in [San Cristobal](https://kokai.app/en/paises/europa/espana/san-cristobal/), where this site lists 47 more places to see, 5.2 km from the centre.

Its coordinates are 43.3403, -2.67069; the nearest main airport is Adolfo Suárez Madrid–Barajas Airport (MAD, Madrid), 326 km as the crow flies. How to get around Spain (train, car, bus) is covered in [its country guide](https://kokai.app/en/paises/europa/espana/#moverse).

- [Where it is](https://www.google.com/maps/search/?api=1&query=43.340303%2C-2.67069)
- [Directions](https://www.google.com/maps/dir/?api=1&destination=43.340303%2C-2.67069)

It is one of the [Nature](https://kokai.app/en/paises/europa/espana/naturaleza/) and [Wildlife](https://kokai.app/en/paises/europa/espana/fauna/) places in Spain. In [Kokai](https://kokai.app/en/) it is already on your trip map next to the places you save yourself, and it goes into a day's plan with one tap.

## When to go

The best time to visit Urdaibai estuary is **April to June and September to October**.

| Mes | Época | Hours of daylight |
| --- | --- | --- |
| January | Possible | 9 h 08 |
| February | Possible | 10 h 17 |
| March | Possible | 11 h 39 |
| April | Best time | 13 h 12 |
| May | Best time | 14 h 30 |
| June | Best time | 15 h 12 |
| July | Possible | 14 h 55 |
| August | Possible | 13 h 47 |
| September | Best time | 12 h 17 |
| October | Best time | 10 h 47 |
| November | Possible | 9 h 27 |
| December | Possible | 8 h 48 |

In June there are 15 h 12 of daylight, and in December, 8 h 48. Daylight hours are calculated from the site's latitude for the 15th of each month; when planning a full day on foot they matter as much as the weather.

| What you come for | Best time | Possible |
| --- | --- | --- |
| Nature | April to June and September to October | November to March and July to August |
| Wildlife | April to June and September to October | November to March and July to August |

It is not the same trip whatever you come for: Urdaibai estuary has a different season depending on what you want to do here, and [Kokai](https://kokai.app/en/) puts it in the right month for you.

When to go to Spain in general, with its festivals and peak seasons, is in [its country guide](https://kokai.app/en/paises/europa/espana/#cuando-ir).

## Before you go to Spain

To enter Spain there are 6 things to sort out before you leave, starting with “Valid ID card or passport”: they are all, with their deadlines, in [the Spain checklist](https://kokai.app/en/paises/europa/espana/#antes-de-salir). Currency: Euro (EUR); plugs: Type C and F · 230 V · 50 Hz; emergencies: 112.

In [Kokai](https://kokai.app/en/) you tick off the checklist inside your trip, and each item reminds you when it is time to do it.

## What is nearby

- [Koba Errota](https://kokai.app/en/paises/europa/espana/koba-errota/): Monument · 1.7 km
- [Castillo de la Emperatriz Eugenia de Montijo](https://kokai.app/en/paises/europa/espana/castillo-de-arteaga/): Chateau in Arteaga, Spain · 1.9 km
- [Gernika-Lumo Forua. Por el corazón del estuario](https://kokai.app/en/paises/europa/espana/gernika-lumo-forua-por-el-corazon-del-estuario/): Hiking · 2.1 km
- [Gautegiz-Arteaga. Recorrido por un arroyo molinero](https://kokai.app/en/paises/europa/espana/gautegiz-arteaga-recorrido-por-un-arroyo-molinero/): Hiking · 2.1 km
- [Santimamiñe](https://kokai.app/en/paises/europa/espana/santimamine/): Cave in Vizkay with prehistoric paintures in Spain · 2.8 km

Distances are as the crow flies. Everything else is in [the Spain guide](https://kokai.app/en/paises/europa/espana/).

## More in Spain: Nature

- [Teide](https://kokai.app/en/paises/europa/espana/teide/): volcano on Tenerife in the Canary Islands
- [Province of Ávila](https://kokai.app/en/paises/europa/espana/el-cabezo/): province in Castile and León, Spain
- [Cave of Altamira](https://kokai.app/en/paises/europa/espana/cueva-de-altamira/): cave with prehistoric paintings in Spain
- [Teide National Park](https://kokai.app/en/paises/europa/espana/parque-nacional-del-teide/): National Park in Tenerife, Spain
- [Park Güell](https://kokai.app/en/paises/europa/espana/parque-guell/): public park system in Barcelona, Spain
- [Aneto](https://kokai.app/en/paises/europa/espana/pico-aneto/): highest mountain of the Pyrenees

Every Spain place under Nature, each with its season, is on [its page](https://kokai.app/en/paises/europa/espana/naturaleza/).

## Frequently asked questions

### What is Urdaibai estuary?

It is a Biosphere reserve in Biscay, Basque Country, Spain (Urdaibaiko Biosfera Erreserba in the local language). It has articles in 11 Wikipedias, so it is not one of the busiest places in Spain: one to enjoy at a calmer pace.

### When is the best time to visit Urdaibai estuary?

April to June and September to October. In June there are 15 h 12 of daylight, and in December, 8 h 48.

### How do you get to Urdaibai estuary?

The nearest main airport is Adolfo Suárez Madrid–Barajas Airport (MAD), 326 km as the crow flies. From there, [directions](https://www.google.com/maps/dir/?api=1&destination=43.340303%2C-2.67069) opens the route on the map, and how to get around Spain is explained in [its country guide](https://kokai.app/en/paises/europa/espana/#moverse).

### How do I add it to my trip?

With one tap. In Kokai it is already on the Spain map, next to the places you save yourself: add it to a day's plan, give it a time and, if you like, get a reminder when you pass nearby.

### What else is around here?

Nearby you have [Koba Errota](https://kokai.app/en/paises/europa/espana/koba-errota/), [Castillo de la Emperatriz Eugenia de Montijo](https://kokai.app/en/paises/europa/espana/castillo-de-arteaga/), [Gernika-Lumo Forua. Por el corazón del estuario](https://kokai.app/en/paises/europa/espana/gernika-lumo-forua-por-el-corazon-del-estuario/). The rest is in [the Spain guide](https://kokai.app/en/paises/europa/espana/).

Data from [OpenStreetMap](https://www.openstreetmap.org/relation/6841341), licensed under the ODbL, and from [Wikidata](https://www.wikidata.org/wiki/Q3118982), CC0. More about Urdaibai estuary on [Wikipedia](https://es.wikipedia.org/wiki/Reserva_de_la_biosfera_de_Urdaibai). Daylight hours are calculated from the latitude. More in [credits](https://kokai.app/en/aviso/#creditos).