Partners in a registered same sex partnership are considered the same as a married couple, meaning a joint tax return has to be filed in Switzerland. Otherwise (if not in a registered partnership), each of you is taxed as a single person and you should file two separate tax returns. If you are unsure whether your partnership is registered (and recognised) in Switzerland, please contact your Deloitte Switzerland representative.
Children below 18 years and children above 18 years (having a valid school attestation) for whom you are supporting 100% of the costs, are considered as dependent even if they are studying and living abroad, unless you are divorced and pay an alimony.
When registering in Switzerland, you have to indicate your religion. Based on this registration, you will be liable to church tax, irrespective of whether or not you are actively practicing/using any religious infrastructure provided by the canton. If you would like to change this, please contact your local tax authorities/registration office.
If you commute to Switzerland on a daily/weekly basis, you are most likely considered as an international cross border/weekly commuter, being tax resident outside Switzerland. You will be tax liable on your employment income on your Swiss workdays only and your employer should withhold Swiss tax at source from your monthly salary. In case you do not work full-time in Switzerland or if an incorrect tax rate has been applied, you may qualify for a so-called tax at source adjustment which needs to be filed before 31 March of the year following the tax year at the very latest. No extension will be granted.
Should you earn more than 90% of the (family) income in Switzerland (including employment income, investment income, real estate income, etc.), there might be a possibility to still file a Swiss tax return. If you think you qualify for such a tax return, please reach out to your Deloitte contact as a registration has to be made before 31 March of the year following the tax year.