Iridium Sat Phone Prepaid SIMsIridium Satellite Phone Prepaid SIM cards give you global coverage with no activation fees. Prepaid Iridium airtime includes prepaid plans, post paid (monthly) plans, and plans that are specifically tailored for maritime use. Useful Information Iridium Prepaid Satellite Phone SIM cards start with zero balance and validity. You can extend your validity by purchasing another prepaid voucher or a 30 day extension (excluding the 75 minute voucher for