Items shipped via EMS (Express Airmail) typically arrive within 4-5 days and those sent via Registered Airmail in about 1 week. Items shipped via Registered SAL (only available for shopping service items, cannot be used for items in the Tenshi Shop Online Shop) take 2+ weeks.
Keep in mind that shipping from Japan can sometimes take time depending on your location and shipping method. There are cases where packages are held up in customs or are temporarily delayed during the international shipping process and simply arrive later than expected, so don’t panic if your item is only slightly behind schedule. If your tracked item becomes lost, an investigation can be opened one month after the original shipping date.