One can also send amazon products manually through USPS. USPS helps in delivering amazon products from the US to Puerto Rico. 

Customers from Puerto Rico who want to buy products from amazon. com can ship their address location to nearby USPS PO in the United States. After the product is delivered to the USPS Post Office, you can call and request the USPS to deliver the product or package through domestic shipping to Puerto Rico. The services of PO will check and recommend the ways of shipping services available by USPS. After that USPS will deliver the package to Puerto Rico. It takes around 2-7 days after the product is delivered to PO.

What are the services provided to ship to Puerto Rico in USPS?

Time: Customers can deliver their packages and letters to Puerto Rico through USPS domestic delivery services because Puerto Rico is an island and a territory of the United States. Priority Mail Express takes two working days to deliver. 

Priority Mail domestic services take 1-3 days after shipment. First-class mail is the best price mailing service that ships envelopes and small packages within 5 working days. 

Media Mail ships in 2-8 business days. USPS Retail Ground services are used for emergency delivery ships in less than 7 working days. 

Weight: The maximum weight USPS accepts to deliver packages and mails to Puerto Rico is 70lbs. One cannot send Alcoholic beverages, Electronic Cigarettes, Weapons, Furs, Precious metals, Plants, Seeds, Tobacco, ammunition, radioactive materials, and chocolates through USPS services to Puerto Rico. 

Cost: Priority Mail Express charges $26.95 at the post office and online to deliver Puerto Rico, pricing options available at a flat rate and variable price. 

The best affordable first-class mail costs $0.58 to ship to Puerto Rico. 

USPS retail ground will charge around $8.50.

FedEx and DHL will provide similar services as USPS.

Conclusion

No, some of the products which are not eligible to ship to Puerto Rico through postal services are not delivered. Few Electronics are banned by the Puerto Rico government that can not be delivered.