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Just the facts · South Dakota

3 Best Foreign Registration Services in South Dakota (2026), Plainly

For foreign registration services in South Dakota, here is our 2026 ranking: Mainstay Filing ($199), SD Registered Agent.org ($199) and South Dakota Registered Agent.co ($199). South Dakota charges $750 to register, and the services add $397 to $497 over three years.
From the LLC Plainly editorial team

Short answer

What the state charges
$750
Attach a certificate?
Yes
After that
$55, annual report
Who to use
Mainstay Filing, SD Registered Agent.org then South Dakota Registered Agent.co

Who we like in South Dakota

The order comes from our five checks: three-year cost first, then how much the price covers.
Our top pick

1. Mainstay Filing: best for companies that keep growing

$199 up front, then $149 a year

Mainstay Filing gets the top spot: $199 over the state fee gets you registered, with the registered agent free in year one and $149 a year after.

Going with SD Registered Agent.org saves $100 over three years, but only a South Dakota company can use it.

Once the free year is up, the registered agent renews at $149.

Your money buys

  • Application prepared and sent
  • Registered agent, free in year one
  • Same price anywhere

The good

  • A service fee of $199
  • First-year agent is on the house
  • One fee for any state

Trade-offs

  • Its agent renewal of $149 is $50 higher than SD Registered Agent.org
A South Dakota favorite

2. SD Registered Agent.org: best for a lean registration

$199 up front, then $99 a year

SD Registered Agent.org comes next since registering costs $199 above the state fee and the agent is covered in year one, then $99 a year.

Your money buys

  • Your South Dakota registration, filed
  • First-year agent comes with it

The good

  • You don't pay for an agent in year one
  • A small renewal of $99
  • Starts at $199 plus the state fee

Trade-offs

  • Your home state needs a different agent
A South Dakota favorite

3. South Dakota Registered Agent.co: best for a low agent renewal

$199 up front, then $99 a year

South Dakota Registered Agent.co comes next since registering costs $199 above the state fee and the agent is covered in year one, then $99 a year.

It charges what SD Registered Agent.org charges, so the order between them is close.

Your money buys

  • Your South Dakota registration, filed
  • First-year agent comes with it

The good

  • Starts at $199 plus the state fee
  • You don't pay for an agent in year one
  • A small renewal of $99

Trade-offs

  • Your home state needs a different agent

At a glance

#WhoFirst yearRenews atThree-year totalCovers
1Mainstay Filing$199$149/yr$497application prepared and sent; registered agent, free in year one; same price anywhereVisit the Mainstay Filing sitePartner link. We may earn money if you buy.
2SD Registered Agent.org$199$99/yr$397Your South Dakota registration, filed; First-year agent comes with itVisit the SD Registered Agent.org sitePartner link. We may earn money if you buy.
3South Dakota Registered Agent.co$199$99/yr$397Your South Dakota registration, filed; First-year agent comes with itVisit the South Dakota Registered Agent.co sitePartner link. We may earn money if you buy.
We read these prices on November 13, 2026. Three years means year one plus two renewals.

Your questions, answered

When does my LLC need to register?

If your LLC was formed elsewhere and plans to work in South Dakota, registering comes first.

sdlegislature.gov, confirmed October 2026 (official)

What should I expect to pay to register?

Budget $750 for the state and $199 for help.

Add up the state's fees across three years and it's $860. sdsos.gov, confirmed October 2026 (official)

What's the application called?

Once the South Dakota Secretary of State approves the Application for Certificate of Authority, Foreign Limited Liability Company, you're registered.

Attach certificate of Existence.

What keeps the registration active?

Annual report, and the cost is $55.

Mark the date: 1st of the anniversary month.

What put number one on top?

It comes down to work taken off your hands, and Mainstay Filing is best at it.

Together, cost across three years and work taken off your hands make up 64% of the score.

Your home state wants an agent too, and one account for both states is easier.

The five checks

South Dakota rules at a glance

ItemThe answerWhere we found it
Registration fee$750sdsos.gov, confirmed October 2026 (official)
Proof of existenceYessdlegislature.gov, confirmed October 2026 (official)
Annual report$55sdlegislature.gov, confirmed October 2026 (official)
Three-year state total$860Added from the rows
How we get the bottom line: filing + report in year two + report in year three + any minimum tax. Open-ended costs are described in the text only.

FAQ

Is one agent enough for both states?

Both states apply their own rules, so your home state still wants an agent. A company that works in every state, like Mainstay Filing, can cover the pair.

After three years, what have I paid?

Mainstay Filing $497; SD Registered Agent.org $397; South Dakota Registered Agent.co $397, and state fees are separate.

How official are these figures?

The state fees come from South Dakota's own documents, and the service prices come from the companies' sites. We put dates on both.

Is hiring help required?

It's your call. You can file on your own if you meet the rules on this page.

Can someone else do the registration?

Yes. Every pick prepares and files it, and the state fee is the same no matter who you pick.

Who tops the list in South Dakota?

Start with Mainstay Filing, followed by SD Registered Agent.org and South Dakota Registered Agent.co.

Official sources and price pages

  1. South Dakota Secretary of State (sdsos.gov), last confirmed August 2026
  2. South Dakota Secretary of State (sosenterprise.sd.gov), last confirmed August 2026
  3. South Dakota yearly filing: Annual (sdlegislature.gov), last confirmed October 2026
  4. South Dakota report due date (sdlegislature.gov), last confirmed August 2026
  5. SDCL 47-34A-203 (sdlegislature.gov), last confirmed August 2026
  6. South Dakota formation fee: Filing (sdsos.gov), last confirmed October 2026
  7. South Dakota formation fee: Filing (sdlegislature.gov), last confirmed October 2026
  8. South Dakota registered agent statute (sdlegislature.gov), last confirmed October 2026
  9. South Dakota Secretary of State (sdsos.gov), last confirmed October 2026
  10. Foreign LLC application for Certificate (sdsos.gov), last confirmed October 2026
  11. SDCL 47-34A-1003, transacting business (sdlegislature.gov), last confirmed October 2026
  12. SDCL 47-34A-1008, effect of not (sdlegislature.gov), last confirmed October 2026
  13. SDCL 47-34A-1001 to 47-34A-1009, foreign (sdlegislature.gov), last confirmed November 2026
  14. South Dakota service page from Mainstay Filing, November 13, 2026
  15. pricing page from SD Registered Agent.org, November 13, 2026
  16. pricing page from South Dakota Registered Agent.co, November 13, 2026