Skip to content
The Formation Desk

Rankings of registered agents, LLC formation and foreign registration services in all 50 states.

Foreign registration picks · South Dakota

3 Best Foreign Registration Services in South Dakota (2026)

The The Formation Desk call for foreign registration services in South Dakota in 2026: South Dakota Registered Agent.co ($199), Mainstay Filing ($199) and SD Registered Agent.org ($199), in that order. South Dakota Registered Agent.co takes the call: $199 plus the state fee, one year of registered agent service included, then $99 a year for the agent.
Written by The Formation Desk editorial team
1
Number one here

1. South Dakota Registered Agent.co: best for adding only South Dakota

$199 for the service, state fee on top; agent $99 a year after year one

Editorial score 9.4 out of 10

The desk picks South Dakota Registered Agent.co: the South Dakota registration for $199, first agent year included, then $99 yearly.

You get an in-state street address as the registered office, and papers served there are scanned into your account.

It wins the three-year cost comparison with Mainstay Filing.

In the price

  • Filing with the state
  • A first year of registered agent service

Strengths

  • The first registered agent year is included
  • The agent costs $99 after year one
  • A $199 registration price, state fee on top

Cons

  • South Dakota only; your home state needs its own agent
  • EIN application will cost you $99 more
Visit South Dakota Registered Agent.coPartner link. We may earn money if you buy. South Dakota Registered Agent.co up close
2
Best for expanding companies

2. Mainstay Filing: best for companies working in more than one state

$199 for the service, $949 due at checkout with the state fee; agent $149 a year after year one

Editorial score 8.9 out of 10

Runner-up, Mainstay Filing: $199 on top of state fees in any state, with the first year of registered agent service included.

Agent service costs nothing in year one and $149 a year from then on, whichever state you register in.

South Dakota Registered Agent.co undercuts Mainstay Filing by $100 over three years, and that is why Mainstay sits lower on cost.

In the price

  • The registration, prepared and filed for you
  • A free registered agent for the first year
  • Free scans of service of process, uploaded the same business day

Strengths

  • Free scans of served papers on the same business day
  • Registered agent costs nothing in year one
  • $199 service fee, state fee on top
  • Same price in all fifty states

Cons

  • Agent renewal of $149 is $50 above South Dakota Registered Agent.co
Visit Mainstay FilingPartner link. We may earn money if you buy. Mainstay Filing up close
3
Best value here

3. SD Registered Agent.org: best for South Dakota registrations only

$199 for the service, state fee on top; agent $99 a year after year one

Editorial score 8.6 out of 10

Third, SD Registered Agent.org: the South Dakota registration for $199, first agent year included, then $99 yearly.

You get an in-state street address as the registered office, and papers served there are scanned into your account.

On price and features there is nothing between South Dakota Registered Agent.co and SD Registered Agent.org, which makes the order a close call.

In the price

  • Filing with the state
  • A first year of registered agent service

Strengths

  • $199 service fee, then the state fee
  • $99 yearly to keep the agent
  • A year of registered agent service comes in the price

Cons

  • South Dakota only; your home state needs its own agent
  • EIN application will cost you $99 more
Visit SD Registered Agent.orgPartner link. We may earn money if you buy. SD Registered Agent.org up close

The desk's 3 picks in brief

Pick Service Desk score Service fee Year two Good for Visit
1 South Dakota Registered Agent.co 9.4 $199 $99/yr The lowest agent renewal we rank here Visit South Dakota Registered Agent.coPartner link. We may earn money if you buy.
2 Mainstay Filing 8.9 $199 $149/yr Companies doing business in several states Visit Mainstay FilingPartner link. We may earn money if you buy.
3 SD Registered Agent.org 8.6 $199 $99/yr The lowest agent renewal we rank here Visit SD Registered Agent.orgPartner link. We may earn money if you buy.

The Formation Desk sets every score out of 10 itself from the weighted criteria on How we rank; customers do not rate anything.

What a South Dakota foreign registration service costs in 2026: year one, renewal and the three-year bill

Service Year one Year two Year three Bill over three years Agent covered in year one
South Dakota Registered Agent.co $199 $99 $99 $397 Included
Mainstay Filing $199 $149 $149 $497 Free
SD Registered Agent.org $199 $99 $99 $397 Included

Every price here was read off the company's own pages on November 12, 2026. South Dakota's $750 registration fee comes on top of every row and is left out of these totals.

What tipped the order

The Formation Desk counts spend over three years and work the price removes for 33% each; what renewal looks like, fit with the state and plain price display make up the other 34%. What tipped South Dakota: spend over three years.

South Dakota Registered Agent.co comes to $397 over three years, $100 less than Mainstay Filing. Both include a first year of agent service, so the renewal price made the call.

The full criteria and weights are on How we rank.

Registering a foreign LLC in South Dakota: fee, form and who gets it

To register, the company files the Application for Certificate of Authority, Foreign Limited Liability Company with the South Dakota Secretary of State and pays the state's $750. South Dakota also wants certificate of Existence.

From then on the company owes the annual report ($55), due 1st of the anniversary month.

What to pull together first

  • Certificate of Existence.
  • The company name exactly as the home state spells it, and when it was formed.
  • An in-state registered agent; any service the desk picked can fill that seat.
  • $750 for the state, paid when you file.
  • A date on your calendar for the annual report and its $55 fee.

What it costs to ignore South Dakota registration

The contracts it signs stay good (SDCL 47-34A-1008(b)).

South Dakota foreign registration service: reader questions

Does an LLC from elsewhere have to register to operate in South Dakota?

Yes, once it starts doing business there.

What will foreign registration cost you in South Dakota?

$750 goes to the state and $199 to the service.

Will South Dakota ask for something from your home state?

Yes: certificate of Existence.

Do you still need a registered agent after you register?

Yes. Keep a registered agent with a street address in the state on file.

Which foreign registration services did the desk rank here?

South Dakota Registered Agent.co ($199), Mainstay Filing ($199) and SD Registered Agent.org ($199), best pick first.

Who is our pick for foreign registration in South Dakota?

South Dakota Registered Agent.co, since $199 over the state fee to register in South Dakota, agent renewing at $99.

More from us

Where the numbers came from

  1. South Dakota Secretary of State, Business Services / Corporations Division, last checked August 2026
  2. South Dakota Secretary of State, Business Services / Corporations Division, last checked August 2026
  3. South Dakota yearly filing: Annual report: fee and how, official source, last checked October 2026
  4. South Dakota report due date, last checked August 2026
  5. SDCL 47-34A-203, last checked August 2026
  6. South Dakota formation fee: Filing fee, official source, last checked October 2026
  7. South Dakota formation fee: Filing fee, official source, last checked October 2026
  8. South Dakota registered agent statute, last checked October 2026
  9. South Dakota Secretary of State, business services, last checked October 2026
  10. Foreign LLC application for Certificate of Authority, last checked October 2026
  11. SDCL 47-34A-1003, transacting business, last checked October 2026
  12. SDCL 47-34A-1008, effect of not registering, last checked October 2026
  13. SDCL 47-34A-1001 to 47-34A-1009, foreign limited liability companies, last checked November 2026
  14. South Dakota Registered Agent.co: pricing and service pages, as of November 12, 2026
  15. Mainstay Filing: South Dakota service page, as of November 12, 2026
  16. SD Registered Agent.org: pricing and service pages, as of November 12, 2026