Hi.Articles 17 and 18 of the UK/Japan tax treaty here deal with pensions. Assuming your company pension is not derived from a government service job (see here), you will not pay UK tax on it if you are non resident in the UK. It will be taxable in Japan instead.My understanding is that if you enter into a flexible drawdown or flex-access drawdown arrangement with your SIPP provider and then become non-UK resident, the income will not be taxable in the UK (as with the company pension) but that if you return to the UK within five years, the income you have drawn will be taxable subject to the 25% tax free proportion. Take a look here, here, here and here (page 6) for confirmation. There would appear to be a £100,000 threshold.For those who leave the UK after 5 April 2013, the "five year period" replaces the "five full tax year period" for the purposes of temporary non-residence.You should discuss your options with your SIPP provider, particularly their understanding on the tax position. You should complete and submit a P85 to HMRC before you leave the UK.I hope this helps but let me know if you have any further questions.