If you have multiple orders you wish to combine into a single shipment, use the Combine Shipments option.
Combine Shipments allows you to combine items from separate orders into a single shipment while maintaining the integrity of each order. This is so ShipStation can accurately communicate shipment statuses and tracking numbers back to your selling channels for each order.
Before You Combine Orders!
Not all selling channels support the shipment update we send after an order has been combined.
At this time, orders combined in ShipStation for Amazon, OpenSky, SellerActive, or TradeGecko will not update correctly on the selling channel, and so we do not recommend combining orders from these selling channels in ShipStation. If you have done so, you will need to manually update the selling channel with your shipment information. See our Integrations Guide for more information.
To ship all items from separate orders together:
Orders that contain multiple items can be expanded in the Orders grid so you can see exactly what items are included in each order without the additional step of opening the Order Details screen. To view the order's items, click the disclosure triangle to the left of the order you wish to view.
If you want to ship only some of the items in each order together, first use the Split into Shipments process to split the items you will not include in the combined shipment into their own shipment. You can then use the above steps to combine the remaining items into a single shipment.
Notes About Combining Shipments
ShipStation will notify the marketplace for each individual order separately, but the customer notification emails will be combined into a single email that lists all the products in the combined shipment.
ShipStation will use the default email template assigned to the store, even if all of the individual orders were set to use a different template.
If using the [Order Number] field replacement for Label Messages, Packing Slips, or Email Templates, ShipStation will use the Order Number for the first order that was created.
If you use ShipStation's Legacy Layout and receive multiple orders that ship to the same destination, you may want to combine them into a single order so you can ship them in a single shipment.
ShipStation also provides Combine Order Alerts to let you know when orders import and can potentially be combined. These alerts appear in a red bubble on your profile icon in the top right of your ShipStation screen.

For a combine order alert to appear, two or more orders must have both a matching customer ID and Ship To address.
Before You Combine Orders!
Not all selling channels support the shipment update we send after an order has been combined.
At this time, orders combined in ShipStation for Amazon, OpenSky, SellerActive, or TradeGecko will not update correctly on the selling channel, and so we do not recommend combining orders from these selling channels in ShipStation. If you have done so, you will need to manually update the selling channel with your shipment information. See our Integrations Guide for more information.
ShipStation will combine all selected orders and their items into the single surviving order, and the other orders will disappear from your Orders grid. These orders cannot be restored, though you can split the order into multiple orders again if necessary (this will result in new order records).
Try ShipStation's New Layout
ShipStation's new layout lets you combine items from multiple orders into a single shipment without combining multiple order records into a single order in ShipStation. This lets the order records in ShipStation always match what you have in your selling channel and produces more accurate order and shipment reports.