Scope and Application The Guidance Notes apply to the geotechnical design@ installation and operation of jack up spudcan foundations. These recommendations are to be used in conjunction with Part 3 of the ABS Rules for Building and Classing Mobile Offshore Drilling Units (MODU Rules). As MODU Classification is not site-specific in nature@ the Owner specifies conditions for which the unit is to be installed. Guidance for site assessment of jackup operability is given in Section 2@ followed by spudcan penetration prediction in single layer soil@ such as clay and sand in Section 3. In strong over soft soil where punchthrough failure is a major concern on design of jackup spudcan foundation@ the recommended prediction methods to calculate spudcan bearing capacity in layered soils are introduced in Section 4@ as well as the mitigation method for reducing punch-through failure. Three steps are suggested in the order of increasing complexity and reducing conservatism for the overall foundation stability assessment in Section 5. The procedure for calculating foundation fixity is presented in Section 6. If the proximity of the spudcan to the pile is less than one spudcan diameter@ detailed analysis is recommended to estimate the severity of spudcan-pile interaction problems as given in Section 7. The footprint characteristics and its influence on spudcan-footprint interaction are presented in Section 8 as well as possible effective mitigation methods in various field conditions. These Guidance Notes are applicable to self-elevating units which undertake drilling@ construction@ support@ wind turbine installation or other offshore activities.