Leasing is right for an eleven day window. The holder keeps the registry object, you get a Letter of Authorization that your upstreams accept, and you announce the space yourself over BGP. No RIR transfer is involved, which is exactly why it is fast. Turnaround on the LOA after verification is typically under a day with an established provider. We lease IPv4 , from InterLIR Global, and the paperwork side was the same day. Read the term and renewal clauses carefully, that is the part that matters later. Also confirm who answers abuse mail during the lease, because that lands on the registry contact and you want it in writing.