The COVID-19 epidemic normalization challenges the operational efficiency of shipping supply chain and the service level of shipping firms. How to cope with these challenges through blockchain technology investment becomes a hot question in the shipping supply chain. Therefore, we explore the shipping firms' blockchain technology investment strategies under a competitive model and investigate the shipping firms' equilibrium outcomes, consumer surplus and social welfare under different scenarios. We demonstrate that blockchain technology investment cost and logistics service transparency combine to influence shipping firms' market demand, optimal market price and profit. Moreover, we find that shipping firms do not (will) invest in blockchain technology when the investment cost of blockchain technology is high (low). When investment costs and logistics service transparency match each other, the shipping firms reach an asymmetric equilibrium, i.e., only one shipping firm adopts blockchain technology. It is noteworthy that when neither shipping firms invest in blockchain technology, the shipping firms may slip into a prisoner's dilemma. We also show that the competition level and the transparency of logistics services increase the possibility of a prisoner's dilemma. Finally, our results show that shipping firms' blockchain technology investments are conducive to increasing social welfare and consumer surplus, but market competition and logistics service transparency constrain the increase in social welfare and consumer surplus.