Private network peering in virtual network environments

A non-transitory, computer-readable, medium storing program instructions, that when executed on or across one or more processors, causes the one or more processors to:

• determine a route table for routing packets between at least a first resource instance of a first virtual network and a second resource instance of a second virtual network, wherein the resources are implemented using host devices of a service provider network that are physically connected via a network substrate of the service provider network, and wherein the first virtual network and the second virtual network are implemented within the service provider network;
• and
• route a network packet over the network substrate from the first resource instance to the second resource instance, wherein the packet is addressed to a private IP address of the second resource instance in the second virtual network as indicated in the route table.

A method, comprising:

• determining a route table for routing packets between at least a first resource instance of a first virtual network and a second resource instance of a second virtual network, wherein the resources are implemented using host devices of a service provider network that are physically connected via a network substrate of the service provider network, and wherein the first virtual network and the second virtual network are implemented within the service provider network;
• and
• routing a network packet over the network substrate from the first resource instance to the second resource instance, wherein the packet is addressed to a private IP address of the second resource instance in the second virtual network as indicated in the route table.