To safely import variable products with WPML and WP All Import, you need to create separate CSV files for each language with a Unique Identifier column. This allows WP All Import to connect the product translations to the default language products. For this to work properly, you need to add an ID number. You cannot use the SKU or other custom fields.
Then, you can move on to importing your taxonomies, the import settings, and importing your products. For a step-by-step guide, please see the page about importing variable products in multiple languages.
