The town of Martaban was the centre of the Burmese military power in Tenasserim, and the advance towards it of the Siamese army would place it in direct communication with that of Burma.

On the 13th of October, therefore, a force, consisting of a wing of the 41st Regiment and the 3rd Madras Infantry, sailed from Rangoon against the town.

The expedition was delayed by light winds and, when it arrived at the mouth of the river, found that every preparation had been made for an obstinate defence.

They learned, from a peasant, that strong works had been erected on every eminence round the town; and that the road from the coast had been cut, and stockaded.
Approach by this route was impossible, for there were twenty miles of country to be traversed; and much of this was under water from the inundations.

It was, therefore, determined to go up the river, although this was so shallow and full of shoals that the navigation was extremely difficult.