pySerial

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Published On:

Jan 23, 2026

Last Updated:

Jan 23, 2026

pySerial is a popular Python library for serial port communication. It is cross-platform and supports Windows, macOS, Linux and BSD.¹

Installation

Install pySerial using a package manager such as pip or uv. For example, to install using uv:

uv add pySerial

Listing Available Serial Ports

To list the available serial ports, you can use the serial.tools.list_ports.comports() function. For example:

import serial.tools.list_ports
ports = serial.tools.list_ports.comports()
for port in ports:
    print(port.device)

Opening a Serial Port

To open a serial port, you can use the serial.Serial() constructor. For example:

import serial
ser = serial.Serial('/dev/ttyUSB0')

The serial.Serial() constructor takes a number of arguments, including the port name, baud rate, timeout, e.t.c. The most common arguments are:

port: The port name to open.
baudrate: The baud rate to use.
timeout: The timeout in seconds.

If you don’t specify a port name, pySerial will create a port object that is in the closed state, and you’ll need to manually open it using the open() method.

Reading and Writing to a Serial Port

To read from a serial port, you can use the read() method. For example:

data = ser.read(100)

This reads up to 100 bytes from the serial port.

Examples

Quick Write Example

import serial
ser = serial.Serial('/dev/ttyUSB0')  # open serial port
ser.write(b'hello')     # write a string
ser.close()             # close port

pySerial. pySerial Documentation - Homepage. Retrieved 2026-01-23, from https://pyserial.readthedocs.io/en/latest/. ↩
pySerial. pySerial Documentation - Short Introduction. Retrieved 2026-01-23, from https://pyserial.readthedocs.io/en/latest/shortintro.html. ↩