A portable boarding ladder is attached to a rubberized portion of an inflatable boat without the use of piercing fasteners and does not require a hard point mounting structure. A base ladder section and a climbing ladder section are pivotally coupled together and supported in an operative, stand-off boarding position along a curved hull surface of a pontoon boat by a pair of hook support brackets and a pair of latch retainer brackets. The support brackets are bonded to the pontoon by adhesive deposits. A lateral cross bar tubing segment of the base ladder section is supported by hanging engagement on the hook brackets. A pair of side rail tubing segments of the climbing ladder section are retained and secured against lateral shifting displacement and rotation relative to the pontoon by snap-fit engagement against resilient arm portions of the latch retainer brackets.