Boskalis sets stock dividend conversion rate at 1:26.5

Papendrecht, 4 June 2010 On 12 May 2010 the dividend of Royal Boskalis Westminster N.V. for 2009 was set at  1.19 per ordinary share with a choice of stock or cash dividend. With the dividend distribution as stock, shareholders will receive 1 new ordinary share per 26.5 dividend rights of ordinary shares. The conversion rate has been based on the volume weighted average stock price of Boskalis shares traded on NYSE Euronext Amsterdam over the period 2, 3 and 4 June 2010. The value of the stock dividend is virtually the same as the value of the cash dividend based on the 1:26.5 conversion rate and an average share price of  31.8058. Both the cash and stock dividend will be made payable from Wednesday 9 June 2010. Cash distribution will be subject to deduction of dividend tax as required by law. This is an English translation of the Dutch press release. In the event of any disparity between the Dutch original and this translation, the Dutch text will prevail. Royal Boskalis Westminster N.V. is a leading global services provider operating in the dredging, maritime infrastructure and maritime services sectors. We provide creative and innovative all-round solutions to infrastructural challenges in the maritime, coastal and delta regions of the world including the construction and maintenance of ports and waterways, land reclamation, coastal defense and riverbank protection. We offer a wide variety of marine services through SMIT and we have positions in strategic partnerships in the Middle East (Archirodon) and in offshore services (Lamnalco). The company holds important home market positions in and outside of Europe. Boskalis has a versatile fleet of over 1,000 units and operates in over 65 countries across six continents. Including its share in partnerships, Boskalis has approximately 14,000 employees. Boskalis celebrates its 100^th anniversary in 2010. For further information please contact: Martijn L.D. Schuttevâer
Director of Investor Relations & Corporate Communications
Telephone:           +31 78 69 69 822 / +31 6 200 10 232
Telefax:                 +31 78 69 69 020               
E-mail:                   m.l.schuttevaer@boskalis.nl This press release can also be found on our website www.boskalis.com