South Dakota writing and signature requirements
A South Dakota premarital agreement must be in writing and signed by both parties and is enforceable without consideration.
S.D. Codified Laws § 25-2-17SD · Manually written guide
Prenup laws in South Dakota
South Dakota's Uniform Premarital Agreement Act in sections 25-2-16 through 25-2-25 addresses formalities, content, effect, amendment, and enforcement.S.D. Codified Laws § 25-2-17S.D. Codified Laws § 25-2-18(a)S.D. Codified Laws § 25-2-21(a)(1)
South Dakota's permitted-subjects text does not track every other uniform-act state, so counsel should use the state's exact language rather than a generic template.S.D. Codified Laws § 25-2-18(a)
Evidence tiersection verified
Package versionsd-2026-07-22.3
Authorities13
Reviewed2026-07-22
Effective through2026-07-22
Formation and lifecycle
Execution requirements to investigate
South Dakota effect of marriage
A South Dakota premarital agreement becomes effective upon marriage.
S.D. Codified Laws § 25-2-19South Dakota amendment and revocation formalities
After marriage, amendment or revocation requires a written agreement signed by the parties and is enforceable without consideration.
S.D. Codified Laws § 25-2-20What the agreement addresses
Permitted subjects and legal limits
South Dakota statutory definitions
South Dakota defines a premarital agreement as one between prospective spouses made in contemplation of marriage and effective upon marriage, and defines property to include present, future, legal, equitable, vested, contingent, real, personal, income, and earnings interests.
S.D. Codified Laws § 25-2-16South Dakota permitted agreement subjects
South Dakota lists property rights and management, disposition, estate-planning arrangements, life-insurance benefits, choice of law, and other lawful personal rights and obligations as permitted subjects.
S.D. Codified Laws § 25-2-18(a)South Dakota child-support limitation
A South Dakota premarital agreement may not adversely affect a child's right to support.
S.D. Codified Laws § 25-2-18(b)South Dakota void-marriage rule
If a marriage is void, an otherwise premarital agreement is enforceable only as necessary to avoid an inequitable result.
S.D. Codified Laws § 25-2-22South Dakota limitation-of-actions rule
South Dakota tolls an applicable limitations period for a claim under a premarital agreement during marriage while preserving equitable time defenses including laches and estoppel.
S.D. Codified Laws § 25-2-23South Dakota uniformity, short title, and enactment history
South Dakota directs uniform construction of sections 25-2-16 through 25-2-25 and designates them as the Uniform Premarital Agreement Act.
S.D. Codified Laws §§ 25-2-24–25South Dakota Supreme Court tracing and construction
Charlson affirmed enforcement and whole-document construction of a premarital agreement whose unambiguous terms preserved separate property despite commingling and permitted contract-specific tracing and marital-loan accounting.
Charlson v. Charlson, 2017 S.D. 11Process evidence
Financial disclosure, voluntariness, counsel, and timing
South Dakota voluntary-execution safeguard
The party resisting enforcement in South Dakota may prove that the agreement was not executed voluntarily.
S.D. Codified Laws § 25-2-21(a)(1)South Dakota unconscionability and disclosure safeguard
South Dakota's execution-time unconscionability ground also requires all three statutory disclosure conditions: no fair and reasonable disclosure, no voluntary express written waiver, and no adequate knowledge of the other party's property or financial obligations.
S.D. Codified Laws § 25-2-21(a)(2), (b)South Dakota Supreme Court voluntariness and disclosure analysis
Eichstadt places the burden on the party avoiding enforcement, reviews voluntariness under the execution circumstances, and requires the separate statutory disclosure findings before an unconscionability ruling.
In re Estate of Eichstadt, 2022 S.D. 78Hypotheticals, not outcomes
Practical examples
These examples show how document facts can intersect with the cited sources. They do not predict a court result.
The spousal-support clause copied from another state
A template imported from another jurisdiction includes a detailed support waiver. South Dakota's distinct content wording makes state-specific review essential.S.D. Codified Laws § 25-2-18(a)
Ask local counsel
Does South Dakota's exact permitted-subjects text authorize and limit this support term?
The agricultural debt disclosure
Land values are listed but operating loans and guarantees are not. South Dakota's enforcement source makes the full property-and-obligation picture relevant.S.D. Codified Laws § 25-2-21(a)(1)
Ask local counsel
Was the financial disclosure sufficient in light of the omitted agricultural obligations?
Common starting points
South Dakota prenup FAQs
Answers are deliberately scoped to the cited evidence package and should be checked against current law.
What is South Dakota's formation section?
Section 25-2-17 supplies the cited writing and signature formalities.S.D. Codified Laws § 25-2-17
Why should the content text be read carefully?
The package notes that section 25-2-18 does not track every other uniform-act state's permitted-subject formulation.S.D. Codified Laws § 25-2-18(a)
Which enforcement section is catalogued?
Section 25-2-21 supplies the state's voluntariness and financial-process safeguards.S.D. Codified Laws § 25-2-21(a)(1)
Prepare for independent advice
Questions for a South Dakota lawyer
Bring the agreement, every exhibit, prior drafts, disclosure records, and a signing timeline. Then use the source-linked questions as an interview guide.
- 01
Does the document fit the statutory definition, and which interests fall within its property terms?S.D. Codified Laws § 25-2-16
- 02
Is the complete agreement, including every incorporated schedule, written and signed by both parties?S.D. Codified Laws § 25-2-17
- 03
Does the agreement contain a support term, and how does current South Dakota authority treat it despite the statutory list's omission?S.D. Codified Laws § 25-2-18(a)
- 04
Does any provision purport to adversely affect a child's support right?S.D. Codified Laws § 25-2-18(b)
- 05
Did the contemplated marriage occur, and on what date did the agreement become effective?S.D. Codified Laws § 25-2-19
- 06
Are all claimed amendments or revocations written and signed by both parties?S.D. Codified Laws § 25-2-20
- 07
What admissible evidence bears on voluntary execution under section 25-2-21 and current South Dakota decisions?S.D. Codified Laws § 25-2-21(a)(1)
- 08
What evidence addresses every part of section 25-2-21(a)(2)?S.D. Codified Laws § 25-2-21(a)(2), (b)
- 09
How could section 25-2-22 affect relief if marriage validity is disputed?S.D. Codified Laws § 25-2-22
- 10
How do tolling and equitable defenses affect the claim timeline?S.D. Codified Laws § 25-2-23
- 11
Does the agreement date or a later amendment require review of historical text or intervening decisions?S.D. Codified Laws §§ 25-2-24–25
- 12
What does this agreement say about commingling, tracing, proceeds, loans, and the burden of proving each asset's character?Charlson v. Charlson, 2017 S.D. 11
- 13
How do Eichstadt's fact-specific voluntariness analysis and separate disclosure requirements apply to the preserved evidence here?In re Estate of Eichstadt, 2022 S.D. 78
Known boundaries
Package limitations
- This package encodes the cited official statutory sections but does not decide how a court would apply them to particular facts.
- Later amendments, decisions, court rules, conflicts rules, and local practice require continuing review.
- Attorney review is optional and can add a professional opinion; this package supports transparent research and issue spotting without prior endorsement.