Post offices are nowadays a service integrated in various shops; grocery stores, kiosks, gasstations etc. The opening hours therefore differ according to the specific store. Generally the post offices are open during normal shopping hours, but local variations may apply. Look for the blue postal sign.
Letters and postcards of up to 20 grams cost SEK 6 within Sweden and SEK 12 internationally.
Stamps are available for sale at post offices, most newsstands and supermarkets with postal service.
There are two different types of mailboxes. The blue box is for local deliveries only, and the yellow box for national and international deliveries.