I’ll introduce the recommended method for simultaneously logging in to multiple Google accounts, including Gmail.

Prepare two-factor authentication app

First, if you haven’t installed a two-factor authentication app, let’s install one.

• Authy is recommended over Google Authenticator for two-factor authentication apps | CodeNote

Steps for using multiple Google accounts

Google multi-login method

When using multiple Google accounts, I recommend using the multi-login feature available in Chrome web browser.

Let’s log in to multiple Google accounts by referring to the following article. It includes login methods for PC, Android, and iOS respectively.

• 複数のアカウントに同時にログインする - パソコン - Google アカウント ヘルプ

Multi-login feature supported environments

It seems to be available with Chrome browser version 37 or later. While it might not need to be mentioned, the multi-login feature is not available in browsers other than Chrome.

In Chrome version 37 and later, if you have multiple profiles set up on Chrome-equipped devices, you can easily switch between profiles without repeatedly logging out and logging in by staying logged in to multiple profiles simultaneously.

Source: マルチログイン アクセスを管理する - Google Chrome Enterprise ヘルプ

That’s all from the Gemba where I want to simultaneously log in to multiple Google accounts and use them together.