Two letters, one country and a surprising amount of word-play. The .si domain belongs to Slovenia, yet it is used by brands, bloggers and even political parties around the world. Here is what it is, why Slovenia ended up with SI instead of SL, who can register one, what it costs and whether it is safe.
What is a .si domain?
A .si domain is a country-code top-level domain (ccTLD), the same family as .uk, .de or .se. It was introduced on April 1, 1992, and is administered by ARNES, the Academic and Research Network of Slovenia, which runs the registry under the name Register.si. Registrations are taken directly at the second level, so your address looks like yourbrand.si.
Wikipedia counted 186,159 registered .si domains in June 2026, up from about 150,000 in 2022. That makes it a small, tidy namespace compared with giants like .com, which also means more short and memorable names are still available.
| Country | Slovenia |
|---|---|
| Introduced | April 1, 1992 |
| Registry | ARNES (Register.si), Ljubljana |
| Registered domains | 186,159 (June 2026, per Wikipedia) |
| Name length | 2 to 63 characters; IDN (non-ASCII) names allowed |
| DNSSEC | Supported |
| Dispute handling | Alternative dispute resolution (ADR) |
Which country is the .si domain?
It is Slovenia's. Country-code domains follow the two-letter codes set by the International Organization for Standardization (ISO), and SI is the code assigned to Slovenia. The same standard is behind postal codes and the codes printed in passports.
Why is Slovenia's domain SI and not SL?
Register.si shares a well-known anecdote: Slovenia wanted .sl, but that extension was already taken by Sierra Leone, so Slovenia received .si in the first half of 1992. Either way, SI is also the country's official ISO code, so the extension fits the standard.
That is why people searching for the "SL domain" often land on the wrong country. .sl belongs to Sierra Leone, not Slovenia. It is usually far more expensive (registrars list it anywhere from about $65 to over $280 a year), and at least two registrars state it lacks DNSSEC support.
Another bit of history: for a short time in 1992 to 1994, Slovenia managed the old .yu domain from Ljubljana before it went back to Belgrade. The .yu extension was removed from the root in 2006, and sites stopped loading on September 30, 2009.
Who can register a .si domain?
Wikipedia and several registrars (including DDOT and domain directories) list no registration restrictions, so individuals and companies anywhere can register. A few directory sites still mention older rules that tie the holder to Slovenia, so confirm the current terms with your registrar at checkout.
Some names are reserved. For example, 113.si is held for the police, 112.si for civil protection, and si.si and rs.si for the Slovenian government, according to ICANNWiki.
How to register a .si domain, step by step
- Pick a name. Use 2 to 63 characters; hyphens are allowed in the middle but not at the start, end or in a row.
- Choose an accredited registrar. Register.si requires its registrars to have an EU business seat or ICANN accreditation, so use a known provider.
- Check availability and compare renewal prices. First-year discounts are common; renewal can be higher.
- Enter accurate owner details. Registrars must keep holder data correct, and WHOIS privacy is not offered everywhere for .si.
- Pay and wait. Processing is usually automatic but some registrars quote 1 to 3 days.
- Set DNS and turn on DNSSEC if your host supports it.
.si domain price in 2026
The price depends almost entirely on the registrar. These are listed prices I found while researching this guide; they change often, so treat them as a snapshot.
| Registrar (example) | Listed price |
|---|---|
| DDOT (first year) | $12.63 (renewal $14.16) |
| DonDominio | €13.95 per year |
| Anycast.io | €28.56 per year |
| Nuxoa | €31.90 per year |
| EuroDNS | €76.50 per year |
| Instra | $169 per year |
Premium short names can cost much more. One registrar's aftermarket list shows a single-word .si name at €1,500.
Is .se a safe domain to use? (And is .si safe too?)
People often mix up .se and .si, so here are both. .se is Sweden's country-code domain, introduced in 1986 and operated by the non-profit Internetstiftelsen (The Swedish Internet Foundation). It supports DNSSEC and had about 1.47 million registered domains in March 2024. The registry is well established and reputable.
.si is run by a public-infrastructure institution, supports DNSSEC, and a 2010 McAfee study ranked Slovenia's extension as the tenth most secure domain in the world. That study is old, so use it as background rather than proof of today's risk.
The honest answer for both: an extension is not "safe" or "unsafe" by itself. Risk comes from the website behind it. Choose a reputable registrar, enable DNSSEC and HTTPS, and be as careful with unknown links on .se or .si as you would be on .com.
.si vs .se vs .sl at a glance
| .si | .se | .sl | |
|---|---|---|---|
| Country | Slovenia | Sweden | Sierra Leone |
| Introduced | 1992 | 1986 | 1997 |
| DNSSEC | Yes | Yes | Not at some registrars |
| Typical price | About €13–35 | Varies by registrar | About $65–280 |
Why brands love .si: the domain-hack effect
In Slovene, si means "you are," and in Spanish sí means "yes." That makes .si a favorite for domain hacks, where the name and extension read as one phrase. Examples include zadovoljna.si ("you are pleased"), Pepsi's short link pep.si, and the video-conferencing tool Jitsi at jit.si. Mexico's MORENA party even uses morena.si.
Pros
- Low cost at many registrars
- Short, clever word-play names
- Strong signal for Slovenian audiences
- DNSSEC and IDN support
Cons
- Seen as "Slovenian" by default
- Prices and renewals vary widely
- WHOIS privacy is not offered everywhere
- Less familiar to global users than .com
Is a .si domain good for SEO?
Search engines generally treat country-code domains as a geographic hint. If your customers are in Slovenia, .si supports local trust and local rankings. If you serve a worldwide audience, a .com or another generic extension avoids the country association, unless your brand depends on the .si word-play. Good content, fast hosting and solid backlinks matter far more than the extension.
Frequently asked questions about .si domains
What is a .si domain?
Which country is the .si domain?
Why is Slovenia's domain SI and not SL?
Can anyone buy a .si domain?
How much does a .si domain cost?
Is .se a safe domain to use?
What is the SL domain?
Is .si good for SEO?
Final verdict: should you buy a .si domain?
Buy a .si domain if you target Slovenia, or if you have a brand or phrase that reads naturally with "si" at the end. It is affordable, secure and open to most buyers. Skip it if you need a neutral global identity and have no word-play to gain. Whichever you choose, compare renewal prices and register through an accredited registrar.
Prices, rules and domain counts change. Verify the latest terms at Register.si and your chosen registrar before you buy.