| Document and Entity Information | Jul. 29, 2021 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | ALPHA HEALTHCARE ACQUISITION CORP III |
| Amendment Flag | false |
| Entity Central Index Key | 0001842939 |
| Document Type | 8-K/A |
| Document Period End Date | Jul. 29, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-40228 |
| Entity Tax Identification Number | 86-1645738 |
| Entity Address, Address Line One | 1177 Avenue of the Americas |
| Entity Address, Address Line Two | 5th Floor |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10036 |
| City Area Code | (646) |
| Local Phone Number | 494-3296 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Units Each Consisting Of One Share Of Class Acommon Stock 0.0001 Par Value Andone Fourth Of A Redeemable Warrant To Acquireone Share Of Class A Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Units, each consisting of one share of Class Acommon stock, $0.0001 par value, andone-fourth of a redeemable Warrant to acquireone share of Class A |
| Trading Symbol | ALPAU |
| Security Exchange Name | NASDAQ |
| Common Class A [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Class A common stock, $0.0001 par value |
| Trading Symbol | ALPA |
| Security Exchange Name | NASDAQ |
| Redeemable Warrants To Acquire One Share Of Class A Common Stock Included As Part Of The Units [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Redeemable warrants to acquire one share ofClass A common stock included as part of theUnits |
| Trading Symbol | ALPAW |
| Security Exchange Name | NASDAQ |
