Australia

Under Australia’s Marriage Act 1961, what matters is the certificate itself: an original or certified copy issued by the competent authority in a foreign country is proof of that marriage and its validity, regardless of who performed the ceremony or whether witnesses were present.

The certificate is the proof, no registration needed

Unlike some countries, Australia doesn’t have an optional-but-common “register it with us anyway” step. Your certified, apostilled Colorado marriage certificate is the document Australian authorities (Centrelink, the tax office, passport applications, whatever the context) will treat as proof of your marriage. See the apostille process for how to get that certificate.

A closed list of reasons a marriage could be refused, and “no officiant” isn’t on it

The Marriage Act 1961 spells this out in more specific terms than “generally recognized.” A foreign marriage qualifies for recognition if it was valid under the law of the place it happened; Colorado’s law clears that bar for a self-solemnized marriage directly. From there, the Act lists specific, narrow grounds on which a foreign marriage involving someone domiciled in Australia won’t be recognized: either party wasn’t of marriageable age, the two of you were within a prohibited relationship (close family), or either party’s consent wasn’t real (obtained by duress, fraud, or mistake). That’s the list. Whether an officiant or witnesses were present isn’t one of the grounds.

This is a genuinely closed statutory list (Marriage Act 1961, Part VA), not an open-ended "we'll know it when we see it" standard, which is a meaningfully stronger basis than a general lex loci assertion alone. We found no Australian case specifically addressing a self-solemnized marriage by name, but the statute itself doesn't leave room for that to matter.

You won’t need a Certificate of No Impediment beforehand

Australia’s Department of Foreign Affairs and Trade (DFAT) can issue a Certificate of No Impediment (CNI) for Australians who are marrying overseas in a country that requires one. Colorado does not require this from foreign nationals; a valid passport is the ID requirement, the same as for any applicant. So this is a document you’re eligible to get if you ever needed it, but not one Colorado will ask you for.

We didn't find any Colorado county clerk documentation requiring a CNI from foreign applicants, which is why this is "you likely won't need one" rather than an absolute guarantee. Requirements are set at the county level and could in principle vary. Confirm with your specific county if you want certainty; see colorado counties compared.

The practical summary

• Your Colorado marriage is valid in Australia as soon as it’s valid in Colorado; no separate Australian approval step exists.
• Your apostilled, certified marriage certificate is the actual document Australian institutions will want to see; keep the original safe and get extra certified copies from your county clerk if you think you’ll need more than one (see getting your apostille after you’ve left Colorado for how to request replacement certified copies later).
• You won’t need a CNI to marry in Colorado in the first place.

See does it matter what country we’re from? for the broader picture of why this varies country to country.