Python Release Python 3.15.0a3 | Python.org

Notice: This page displays a fallback because interactive scripts did not run. Possible causes include disabled JavaScript or failure to load scripts or stylesheets. Note: Python 3.15.0a3 has been superseded by Python 3.15.0a6. Release date: Dec. 16, 2025 This is an early developer preview of Python 3.15 Major new features of the 3.15 series, compared to 3.14 Python 3.15 is still in development. This release, 3.15.0a3, is the third of seven planned alpha releases. Alpha releases are intended to make it easier to test the current state of new features and bug fixes and to test the release process. During the alpha phase, features may be added up until the start of the beta phase (2026-05-05) and, if necessary, may be modified or deleted up until the release candidate phase (2026-07-28). Please keep in mind that this is a preview release and its use is not recommended for production environments. Many new features for Python 3.15 are still being planned and written. Among the new major new features and changes so far: PEP 799: A new high-frequency, low-overhead, statistical sampling profiler and dedicated profiling package PEP 686: Python now uses UTF-8 as the default encoding PEP 782: A new PyBytesWriter C API to create a Python bytes object Improved error messages (Hey, fellow core developer, if a feature you find important is missing from this list, let Hugo know.) The next pre-release of Python 3.15 will be 3.15.0a4, currently scheduled for 2026-01-13. More resources Online documentation PEP 790, 3.15 release schedule Report bugs at https://github.com/python/cpython/issues Help fund Python directly (or via GitHub Sponsors) and support the Python community And now for something completely different Instantly the captain ran forward, and in a loud voice commanded his crew to desist from hoisting the cutting-tackles, and at once cast loose the cables and chains confining the whales to the ship. “What now?” said the Guernsey-man, when the Captain had returned to them. “Why, let me see; yes, you may as well tell him now that—that—in fact, tell him I’ve diddled him, and (aside to himself) perhaps somebody else.” Enjoy the new release Thanks to all of the many volunteers who help make Python Development and these releases possible! Please consider supporting our efforts by volunteering yourself or through organisation contributions to the Python Software Foundation. Full Changelog macOS Download macOS installer Windows Download Python install manager Source release Download XZ compressed source tarball Version Operating system Description File size Sigstore SBOM MD5 checksum Gzipped source tarball Source release 40.6 MB .sigstore SPDX 2d5db2f28324577846fad0fda7389994 XZ compressed source tarball Source release 33.1 MB .sigstore SPDX d6ee7c74b9618520e88ec175f5539623 Android embeddable package (aarch64) Android 20.9 MB .sigstore 6ea85f675dfd621ffbd20358a407238b Android embeddable package (x86_64) Android 21.2 MB .sigstore f5aee27a4aba76592c212a6ef78c3593 macOS installer macOS for macOS 10.15 and later 86.1 MB .sigstore 6d465ce19df3664f12fd19dfc18fa624 Windows installer (64-bit) Windows Recommended 39.4 MB .sigstore SPDX b1aa535849569453127c2935b27b42c6 Windows installer (32-bit) Windows 38.0 MB .sigstore SPDX 4d343f22b2fa2811b58b09054b1d16f4 Windows installer (ARM64) Windows Experimental 38.6 MB .sigstore SPDX 1f279eeea133c7447eafef57e474a881 Windows embeddable package (64-bit) Windows 12.0 MB .sigstore SPDX d99611ff8b887880885d10d796a57652 Windows embeddable package (32-bit) Windows 10.7 MB .sigstore SPDX b0e29af281a5d37e521eea1d7a21da16 Windows embeddable package (ARM64) Windows 11.3 MB .sigstore SPDX 07d3f41d0e25e1c220e3241e20091ef0 Windows release manifest Windows Install with 'py install 3.15' 15.3 KB .sigstore 093048797aca9f65de6266059a518150