When is tax due on RSU's after IPO with 6 months lock up period

[angryInch]

If I have RSU's in a company (with the typical time and liquidity vesting - so they only have value after a liquidity event), and the company IPO's with a 6 month lock-up period where they cannot be sold, when is the tax due on them now?
Is it only after the lock up period elapses?

 

[ClubMan]

Restricted Stock Units (RSUs)

The page outlines the taxation of Restricted Stock Units (RSUs)

www.revenue.ie

Share-settled RSUs​

You must pay Income Tax, Universal Social Charge (USC) and Pay Related Social Insurance (PRSI) on the market value of these shares at the date of vesting.

You will be charged tax on the vesting date or on the date the shares pass to you, if earlier. Your employer will make the necessary deductions through payroll and pay the tax directly to the Collector-General.

 

[angryInch]

Thanks @ClubMan