How to create an Anaconda environment with a specific Python version

Project code can silently run under the wrong interpreter when base and the project environment use different Python releases. Creating the environment with a python= version constraint makes Conda solve the interpreter and its dependency set together before any project packages are installed.

The conda create command accepts package specifications during environment creation. A specification such as python=3.11 asks the solver for a compatible Python 3.11 build from the active channels, creates the environment under Conda's environment directory, and records the installed packages in that environment only.

Channel policy matters before the solver can read package metadata. Anaconda's defaults channels may require Terms of Service acceptance, while a project that uses conda-forge or an internal channel should configure those channels before creating the environment so the first solve uses the intended source.

1. Resolve any Anaconda channel Terms of Service blocker shown by Conda.

   $ conda tos accept --override-channels --channel https://repo.anaconda.com/pkgs/main
   accepted Terms of Service for https://repo.anaconda.com/pkgs/main
   
   $ conda tos accept --override-channels --channel https://repo.anaconda.com/pkgs/r
   accepted Terms of Service for https://repo.anaconda.com/pkgs/r

   Accept channel terms only after reviewing them and confirming that the channel is allowed for the environment. If defaults is not allowed, remove or replace that channel before creating the environment.

2. Create the environment with the requested Python version.

   $ conda create --name py311-lab python=3.11 --yes
   2 channel Terms of Service accepted
   Channels:
    - defaults
   Platform: linux-aarch64
   Collecting package metadata (repodata.json): done
   Solving environment: done
   
   ## Package Plan ##
   
     environment location: /opt/conda/envs/py311-lab
   
     added / updated specs:
       - python=3.11
   
   The following NEW packages will be INSTALLED:
   
     python             pkgs/main/linux-aarch64::python-3.11.15-hdc5b1c3_1
     pip                pkgs/main/noarch::pip-26.1.1-pyhc872135_1
     setuptools         pkgs/main/linux-aarch64::setuptools-82.0.1-py311hd43f75c_0
     wheel              pkgs/main/linux-aarch64::wheel-0.46.3-py311hd43f75c_0
   ##### snipped #####
   
   Preparing transaction: done
   Verifying transaction: done
   Executing transaction: done
   #
   # To activate this environment, use
   #
   #     $ conda activate py311-lab
   #

   Replace py311-lab with the environment name and python=3.11 with the required minor version. Leave off --yes when the package plan should pause for interactive confirmation.

3. Confirm that the environment was created.

   $ conda env list
   
   # conda environments:
   #
   # * -> active
   # + -> frozen
   base                     /opt/conda
   py311-lab                /opt/conda/envs/py311-lab

4. Activate the new environment.

   $ conda activate py311-lab
   (py311-lab) $

   If activation is not recognized, initialize Conda for the current shell and reopen the terminal before retrying.
   Related: How to initialize Conda for a shell
   Related: How to activate a Conda environment

5. Verify the active environment uses the requested Python release.

   (py311-lab) $ python --version
   Python 3.11.15

   The patch version may be newer than the version shown here. The first two components should match the requested minor release, such as 3.11.

6. Confirm that Python resolves from the new environment prefix.

   (py311-lab) $ python -c "import sys; print(sys.executable)"
   /opt/conda/envs/py311-lab/bin/python

   The path should point inside the new environment, not inside base or the system Python installation.