Introduction

Installing pip for Python 3.5 in 2026 is mostly a legacy-environment task. The important thing to know is that the current pip release no longer supports Python 3.5. As of March 7, 2026, the newest pip on PyPI that still supports Python 3.5 is 20.3.4. So the goal is not "install the newest pip," but "install a Python 3.5-compatible pip release."

First Try ensurepip

Many Python 3.5 installations already include ensurepip, which can bootstrap pip without downloading a third-party installer script.

python3.5 -m ensurepip --upgrade

Then check what you got:

python3.5 -m pip --version

If that works, you now have a baseline pip installation attached to Python 3.5.

Upgrade Only To A Compatible pip Version

Do not run a plain unrestricted upgrade such as this:

python3.5 -m pip install --upgrade pip

That can try to pull a release line that no longer supports Python 3.5.

Instead, pin a compatible version explicitly:

python3.5 -m pip install --upgrade "pip==20.3.4"

That gives you the newest pip line still compatible with Python 3.5, based on current PyPI metadata.

If ensurepip Is Missing

Some distro-managed Python installations do not include ensurepip. In that case, use your operating system's package manager or a compatible bootstrap path for that Python runtime.

The next best approach is usually:

• install the OS package that provides pip for Python 3.5
• or bootstrap with a compatible installer source for old Python versions
• then immediately pin to pip==20.3.4

The exact package names vary by distribution, so the best package-manager command is platform-specific.

Verify You Are Talking To Python 3.5

Legacy systems often have several Python interpreters installed. Always invoke pip through the interpreter you actually mean to target.

Good:

python3.5 -m pip --version

Risky:

pip --version

The second form may point at a different Python installation entirely.

Use A Virtual Environment If Possible

Even for old runtimes, isolation still matters.

1python3.5 -m venv .venv
2source .venv/bin/activate
3python -m ensurepip --upgrade
4python -m pip install --upgrade "pip==20.3.4"

This avoids contaminating the system interpreter and makes the legacy environment easier to reproduce.

Be Realistic About Python 3.5

Python 3.5 is end-of-life. That means:

• many modern packages will not install
• security support is over
• documentation and ecosystem examples increasingly assume newer Python versions

So installing pip successfully is only part of the story. The surrounding dependency ecosystem may still be difficult.

If you are not forced to keep Python 3.5, upgrading Python is the better long-term answer.

Verify With A Small Package Install

After bootstrapping pip, test it with a tiny package install that still supports old Python environments in your setup. The point is not the package itself. The point is confirming that pip, TLS, and index access all work correctly through the Python 3.5 interpreter.

Common Pitfalls

• Running an unrestricted pip self-upgrade and ending up with a version that no longer supports Python 3.5.
• Using pip directly instead of python3.5 -m pip, then modifying the wrong interpreter.
• Assuming every Python 3.5 install includes ensurepip.
• Forgetting that even with pip installed, many current packages no longer support Python 3.5.
• Treating a legacy runtime as a normal modern Python environment.

Summary

• For Python 3.5, start with python3.5 -m ensurepip --upgrade if available.
• Pin pip to a Python 3.5-compatible release such as 20.3.4.
• Always invoke pip through the exact Python 3.5 interpreter.
• Prefer a virtual environment even for legacy setups.
• If possible, upgrade off Python 3.5 instead of investing further in the legacy toolchain.